640606523400 has 144 divisors (see below), whose sum is σ = 2158379823600. Its totient is φ = 170271815040.

The previous prime is 640606523399. The next prime is 640606523429. The reversal of 640606523400 is 4325606046.

640606523400 is a `hidden beast` number, since 6 + 4 + 0 + 606 + 5 + 2 + 3 + 40 + 0 = 666.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 27030 + ... + 1132229.

It is an arithmetic number, because the mean of its divisors is an integer number (14988748775).

Almost surely, 2^640606523400 is an apocalyptic number.

640606523400 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 640606523400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1079189911800).

640606523400 is an abundant number, since it is smaller than the sum of its proper divisors (1517773300200).

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

640606523400 is a wasteful number, since it uses less digits than its factorization.

640606523400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1159588 (or 1159576 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The spelling of 640606523400 in words is "six hundred forty billion, six hundred six million, five hundred twenty-three thousand, four hundred".