640698206400 has 2100 divisors, whose sum is σ = 2882157070320. Its totient is φ = 139403980800.

The previous prime is 640698206383. The next prime is 640698206419. The reversal of 640698206400 is 4602896046.

It is a tau number, because it is divible by the number of its divisors (2100).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 299 ways as a sum of consecutive naturals, for example, 9023918365 + ... + 9023918435.

Almost surely, 2^640698206400 is an apocalyptic number.

640698206400 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 640698206400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1441078535160).

640698206400 is an abundant number, since it is smaller than the sum of its proper divisors (2241458863920).

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

640698206400 is an equidigital number, since it uses as much as digits as its factorization.

640698206400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 45.

The spelling of 640698206400 in words is "six hundred forty billion, six hundred ninety-eight million, two hundred six thousand, four hundred".