641391206400 has 504 divisors, whose sum is σ = 2625727787904. Its totient is φ = 146600755200.

The previous prime is 641391206387. The next prime is 641391206419. The reversal of 641391206400 is 4602193146.

641391206400 is a `hidden beast` number, since 6 + 4 + 1 + 3 + 9 + 1 + 2 + 0 + 640 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (504).

It is a super-2 number, since 2×641391206400² (a number of 24 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 12877545 + ... + 12927255.

Almost surely, 2^641391206400 is an apocalyptic number.

641391206400 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 641391206400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1312863893952).

641391206400 is an abundant number, since it is smaller than the sum of its proper divisors (1984336581504).

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

641391206400 is a wasteful number, since it uses less digits than its factorization.

641391206400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49760 (or 49728 counting only the distinct ones).

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

Adding to 641391206400 its reverse (4602193146), we get a palindrome (645993399546).

The spelling of 641391206400 in words is "six hundred forty-one billion, three hundred ninety-one million, two hundred six thousand, four hundred".