661593531456 has 945 divisors, whose sum is σ = 2364164067573. Its totient is φ = 182718581760.

The previous prime is 661593531433. The next prime is 661593531457. The reversal of 661593531456 is 654135395166.

The square root of 661593531456 is 813384.

It is a perfect power (a square), and thus also a powerful number.

661593531456 is a `hidden beast` number, since 6 + 6 + 1 + 59 + 3 + 531 + 4 + 56 = 666.

It can be written as a sum of positive squares in only one way, i.e., 97868865600 + 563724665856 = 312840^2 + 750816^2 .

It is a super-2 number, since 2×661593531456² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

Its product of digits (8748000) is a multiple of the sum of its prime divisors (108).

It is not an unprimeable number, because it can be changed into a prime (661593531457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 8374601625 + ... + 8374601703.

Almost surely, 2^661593531456 is an apocalyptic number.

661593531456 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

661593531456 is the 813384-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661593531456

661593531456 is an abundant number, since it is smaller than the sum of its proper divisors (1702570536117).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661593531456 is a wasteful number, since it uses less digits than its factorization.

661593531456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230 (or 108 counting only the distinct ones).

The product of its digits is 8748000, while the sum is 54.

The spelling of 661593531456 in words is "six hundred sixty-one billion, five hundred ninety-three million, five hundred thirty-one thousand, four hundred fifty-six".