621823021 has 4 divisors (see below), whose sum is σ = 622013472. Its totient is φ = 621632572.

The previous prime is 621822989. The next prime is 621823031. The reversal of 621823021 is 120328126.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 621823021 - 2⁵ = 621822989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621823031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 90241 + ... + 96886.

It is an arithmetic number, because the mean of its divisors is an integer number (155503368).

Almost surely, 2^621823021 is an apocalyptic number.

It is an amenable number.

621823021 is a deficient number, since it is larger than the sum of its proper divisors (190451).

621823021 is a wasteful number, since it uses less digits than its factorization.

621823021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190450.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 621823021 is about 24936.3794685596. The cubic root of 621823021 is about 853.5368297061.

The spelling of 621823021 in words is "six hundred twenty-one million, eight hundred twenty-three thousand, twenty-one".