621878993 has 2 divisors, whose sum is σ = 621878994. Its totient is φ = 621878992.

The previous prime is 621878963. The next prime is 621879007. The reversal of 621878993 is 399878126.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 417303184 + 204575809 = 20428^2 + 14303^2 .

It is a cyclic number.

It is not a de Polignac number, because 621878993 - 2²⁰ = 620830417 is a prime.

It is not a weakly prime, because it can be changed into another prime (621878923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310939496 + 310939497.

It is an arithmetic number, because the mean of its divisors is an integer number (310939497).

Almost surely, 2^621878993 is an apocalyptic number.

It is an amenable number.

621878993 is a deficient number, since it is larger than the sum of its proper divisors (1).

621878993 is an equidigital number, since it uses as much as digits as its factorization.

621878993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1306368, while the sum is 53.

The square root of 621878993 is about 24937.5017393483. The cubic root of 621878993 is about 853.5624386701.

The spelling of 621878993 in words is "six hundred twenty-one million, eight hundred seventy-eight thousand, nine hundred ninety-three".