621636642 has 96 divisors (see below), whose sum is σ = 1558440000. Its totient is φ = 177102720.

The previous prime is 621636641. The next prime is 621636689. The reversal of 621636642 is 246636126.

621636642 is a `hidden beast` number, since 6 + 2 + 1 + 6 + 3 + 6 + 642 = 666.

It is a super-2 number, since 2×621636642² = 772864229354072328, which contains 22 as substring.

Its product of digits (62208) is a multiple of the sum of its prime factors (1296).

It is a junction number, because it is equal to n+sod(n) for n = 621636597 and 621636606.

It is not an unprimeable number, because it can be changed into a prime (621636641) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 559984 + ... + 561092.

It is an arithmetic number, because the mean of its divisors is an integer number (16233750).

Almost surely, 2^621636642 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 621636642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (779220000).

621636642 is an abundant number, since it is smaller than the sum of its proper divisors (936803358).

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

621636642 is a wasteful number, since it uses less digits than its factorization.

621636642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1296 (or 1293 counting only the distinct ones).

The product of its digits is 62208, while the sum is 36.

The square root of 621636642 is about 24932.6420982615. The cubic root of 621636642 is about 853.4515443265.

The spelling of 621636642 in words is "six hundred twenty-one million, six hundred thirty-six thousand, six hundred forty-two".