640622400 has 252 divisors, whose sum is σ = 2312310336. Its totient is φ = 155161600.

The previous prime is 640622399. The next prime is 640622419. The reversal of 640622400 is 4226046.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

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, 580249 + ... + 581351.

Almost surely, 2^640622400 is an apocalyptic number.

640622400 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 640622400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1156155168).

640622400 is an abundant number, since it is smaller than the sum of its proper divisors (1671687936).

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

640622400 is a wasteful number, since it uses less digits than its factorization.

640622400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1150 (or 1124 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 640622400 is about 25310.5195521546. The cubic root of 640622400 is about 862.0531438678.

Adding to 640622400 its reverse (4226046), we get a palindrome (644848446).

The spelling of 640622400 in words is "six hundred forty million, six hundred twenty-two thousand, four hundred".