640088400 has 240 divisors, whose sum is σ = 2361876608. Its totient is φ = 145152000.

The previous prime is 640088399. The next prime is 640088417. The reversal of 640088400 is 4880046.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1520190 + ... + 1520610.

Almost surely, 2^640088400 is an apocalyptic number.

640088400 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 640088400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1180938304).

640088400 is an abundant number, since it is smaller than the sum of its proper divisors (1721788208).

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

640088400 is a wasteful number, since it uses less digits than its factorization.

640088400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630 (or 619 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 30.

The square root of 640088400 is about 25299.9683794269. The cubic root of 640088400 is about 861.8135516916.

The spelling of 640088400 in words is "six hundred forty million, eighty-eight thousand, four hundred".