641696400 has 90 divisors (see below), whose sum is σ = 2226877250. Its totient is φ = 171118080.

The previous prime is 641696359. The next prime is 641696401. The reversal of 641696400 is 4696146.

641696400 is a `hidden beast` number, since 6 + 4 + 1 + 6 + 9 + 640 + 0 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 170459136 + 471237264 = 13056^2 + 21708^2 .

It is a tau number, because it is divible by the number of its divisors (90).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (641696401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 85525 + ... + 92724.

Almost surely, 2^641696400 is an apocalyptic number.

641696400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

641696400 is an abundant number, since it is smaller than the sum of its proper divisors (1585180850).

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

641696400 is a wasteful number, since it uses less digits than its factorization.

641696400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178273 (or 178259 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 641696400 is about 25331.7271420644. The cubic root of 641696400 is about 862.5346173881.

The spelling of 641696400 in words is "six hundred forty-one million, six hundred ninety-six thousand, four hundred".