645623602500 has 120 divisors (see below), whose sum is σ = 1891392535648. Its totient is φ = 171349920000.

The previous prime is 645623602487. The next prime is 645623602523. The reversal of 645623602500 is 5206326546.

It is a super-2 number, since 2×645623602500² (a number of 24 digits) contains 22 as substring.

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 39 ways as a sum of consecutive naturals, for example, 1378512 + ... + 1786488.

Almost surely, 2^645623602500 is an apocalyptic number.

645623602500 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 645623602500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (945696267824).

645623602500 is an abundant number, since it is smaller than the sum of its proper divisors (1245768933148).

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

645623602500 is a wasteful number, since it uses less digits than its factorization.

645623602500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 408215 (or 408198 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 39.

The spelling of 645623602500 in words is "six hundred forty-five billion, six hundred twenty-three million, six hundred two thousand, five hundred".