661425756480 has 1120 divisors, whose sum is σ = 2642140512000. Its totient is φ = 156083355648.

The previous prime is 661425756457. The next prime is 661425756517. The reversal of 661425756480 is 84657524166.

661425756480 is a `hidden beast` number, since 6 + 6 + 1 + 4 + 2 + 575 + 64 + 8 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 1666059642 + ... + 1666060038.

Almost surely, 2^661425756480 is an apocalyptic number.

661425756480 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661425756480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1321070256000).

661425756480 is an abundant number, since it is smaller than the sum of its proper divisors (1980714755520).

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

661425756480 is a wasteful number, since it uses less digits than its factorization.

661425756480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 661 (or 642 counting only the distinct ones).

The product of its (nonzero) digits is 9676800, while the sum is 54.

The spelling of 661425756480 in words is "six hundred sixty-one billion, four hundred twenty-five million, seven hundred fifty-six thousand, four hundred eighty".