661323649536 has 120 divisors (see below), whose sum is σ = 2082136337424. Its totient is φ = 200401090560.

The previous prime is 661323649531. The next prime is 661323649559. The reversal of 661323649536 is 635946323166.

661323649536 is a `hidden beast` number, since 6 + 6 + 1 + 32 + 36 + 49 + 536 = 666.

It is a super-2 number, since 2×661323649536² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (661323649531) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6472786 + ... + 6574161.

Almost surely, 2^661323649536 is an apocalyptic number.

661323649536 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

661323649536 is an abundant number, since it is smaller than the sum of its proper divisors (1420812687888).

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

661323649536 is a wasteful number, since it uses less digits than its factorization.

661323649536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13046982 (or 13046963 counting only the distinct ones).

The product of its digits is 12597120, while the sum is 54.

The spelling of 661323649536 in words is "six hundred sixty-one billion, three hundred twenty-three million, six hundred forty-nine thousand, five hundred thirty-six".