621992621 has 4 divisors (see below), whose sum is σ = 629486592. Its totient is φ = 614498652.

The previous prime is 621992599. The next prime is 621992627. The reversal of 621992621 is 126299126.

621992621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 126299126 = 2 ⋅63149563.

It is a cyclic number.

It is not a de Polignac number, because 621992621 - 2²² = 617798317 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 (621992627) 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, 3746861 + ... + 3747026.

It is an arithmetic number, because the mean of its divisors is an integer number (157371648).

Almost surely, 2^621992621 is an apocalyptic number.

It is an amenable number.

621992621 is a deficient number, since it is larger than the sum of its proper divisors (7493971).

621992621 is an equidigital number, since it uses as much as digits as its factorization.

621992621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7493970.

The product of its digits is 23328, while the sum is 38.

The square root of 621992621 is about 24939.7798907689. The cubic root of 621992621 is about 853.6144223558.

The spelling of 621992621 in words is "six hundred twenty-one million, nine hundred ninety-two thousand, six hundred twenty-one".