661430256320 has 56 divisors (see below), whose sum is σ = 1579789452048. Its totient is φ = 263772748800.

The previous prime is 661430256287. The next prime is 661430256379. The reversal of 661430256320 is 23652034166.

It is a happy number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 3016391 + ... + 3228230.

Almost surely, 2^661430256320 is an apocalyptic number.

It is an amenable number.

661430256320 is an abundant number, since it is smaller than the sum of its proper divisors (918359195728).

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

661430256320 is a wasteful number, since it uses less digits than its factorization.

661430256320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6244969 (or 6244959 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 38.

The spelling of 661430256320 in words is "six hundred sixty-one billion, four hundred thirty million, two hundred fifty-six thousand, three hundred twenty".