621881538 has 16 divisors (see below), whose sum is σ = 1262327520. Its totient is φ = 204199776.

The previous prime is 621881501. The next prime is 621881551. The reversal of 621881538 is 835188126.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 621881538.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 773083 + ... + 773886.

It is an arithmetic number, because the mean of its divisors is an integer number (78895470).

Almost surely, 2^621881538 is an apocalyptic number.

621881538 is an abundant number, since it is smaller than the sum of its proper divisors (640445982).

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

621881538 is a wasteful number, since it uses less digits than its factorization.

621881538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1547041.

The product of its digits is 92160, while the sum is 42.

The square root of 621881538 is about 24937.5527668615. The cubic root of 621881538 is about 853.5636030518.

The spelling of 621881538 in words is "six hundred twenty-one million, eight hundred eighty-one thousand, five hundred thirty-eight".