641951595565920 has 576 divisors, whose sum is σ = 2297147198201856. Its totient is φ = 169285540515840.

The previous prime is 641951595565901. The next prime is 641951595565963. The reversal of 641951595565920 is 29565595159146.

641951595565920 is a `hidden beast` number, since 6 + 4 + 1 + 9 + 5 + 1 + 59 + 5 + 565 + 9 + 2 + 0 = 666.

It is a Smith number, since the sum of its digits (72) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1515680580 + ... + 1516104060.

It is an arithmetic number, because the mean of its divisors is an integer number (3988102774656).

Almost surely, 2^{641951595565920} is an apocalyptic number.

641951595565920 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 641951595565920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1148573599100928).

641951595565920 is an abundant number, since it is smaller than the sum of its proper divisors (1655195602635936).

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

641951595565920 is a wasteful number, since it uses less digits than its factorization.

641951595565920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423945 (or 423925 counting only the distinct ones).

The product of its (nonzero) digits is 656100000, while the sum is 72.

The spelling of 641951595565920 in words is "six hundred forty-one trillion, nine hundred fifty-one billion, five hundred ninety-five million, five hundred sixty-five thousand, nine hundred twenty".