640722600 has 288 divisors, whose sum is σ = 2481061440. Its totient is φ = 145152000.

The previous prime is 640722587. The next prime is 640722613. The reversal of 640722600 is 6227046.

It is an interprime number because it is at equal distance from previous prime (640722587) and next prime (640722613).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2658480 + ... + 2658720.

Almost surely, 2^640722600 is an apocalyptic number.

640722600 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 640722600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1240530720).

640722600 is an abundant number, since it is smaller than the sum of its proper divisors (1840338840).

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

640722600 is a wasteful number, since it uses less digits than its factorization.

640722600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481 (or 469 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 640722600 is about 25312.4988888889. The cubic root of 640722600 is about 862.0980862145.

Adding to 640722600 its reverse (6227046), we get a palindrome (646949646).

The spelling of 640722600 in words is "six hundred forty million, seven hundred twenty-two thousand, six hundred".