621440165601 has 24 divisors (see below), whose sum is σ = 917773184640. Its totient is φ = 405019240416.

The previous prime is 621440165597. The next prime is 621440165681. The reversal of 621440165601 is 106561044126.

621440165601 is a `hidden beast` number, since 6 + 2 + 1 + 4 + 40 + 1 + 6 + 5 + 601 = 666.

It is not a de Polignac number, because 621440165601 - 2² = 621440165597 is a prime.

It is not an unprimeable number, because it can be changed into a prime (621440165681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 458386 + ... + 1205403.

It is an arithmetic number, because the mean of its divisors is an integer number (38240549360).

Almost surely, 2^621440165601 is an apocalyptic number.

It is an amenable number.

621440165601 is a deficient number, since it is larger than the sum of its proper divisors (296333019039).

621440165601 is a wasteful number, since it uses less digits than its factorization.

621440165601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1664725 (or 1664722 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 621440165601 in words is "six hundred twenty-one billion, four hundred forty million, one hundred sixty-five thousand, six hundred one".