621421644 has 24 divisors (see below), whose sum is σ = 1463289520. Its totient is φ = 205239744.

The previous prime is 621421643. The next prime is 621421667. The reversal of 621421644 is 446124126.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (621421643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 236239 + ... + 238854.

Almost surely, 2^621421644 is an apocalyptic number.

It is an amenable number.

621421644 is an abundant number, since it is smaller than the sum of its proper divisors (841867876).

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

621421644 is a wasteful number, since it uses less digits than its factorization.

621421644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475209 (or 475207 counting only the distinct ones).

The product of its digits is 9216, while the sum is 30.

The square root of 621421644 is about 24928.3301486481. The cubic root of 621421644 is about 853.3531419691.

The spelling of 621421644 in words is "six hundred twenty-one million, four hundred twenty-one thousand, six hundred forty-four".