661606530400 has 72 divisors (see below), whose sum is σ = 1710155621160. Its totient is φ = 249075394560.

The previous prime is 661606530367. The next prime is 661606530421. The reversal of 661606530400 is 4035606166.

It is a super-2 number, since 2×661606530400² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 661606530400.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24310170 + ... + 24337369.

It is an arithmetic number, because the mean of its divisors is an integer number (23752161405).

Almost surely, 2^661606530400 is an apocalyptic number.

It is an amenable number.

661606530400 is an abundant number, since it is smaller than the sum of its proper divisors (1048549090760).

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

661606530400 is a wasteful number, since it uses less digits than its factorization.

661606530400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48647576 (or 48647563 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 37.

The spelling of 661606530400 in words is "six hundred sixty-one billion, six hundred six million, five hundred thirty thousand, four hundred".