621818993 has 2 divisors, whose sum is σ = 621818994. Its totient is φ = 621818992.

The previous prime is 621818969. The next prime is 621819017. The reversal of 621818993 is 399818126.

It is a balanced prime because it is at equal distance from previous prime (621818969) and next prime (621819017).

It can be written as a sum of positive squares in only one way, i.e., 621604624 + 214369 = 24932^2 + 463^2 .

It is a cyclic number.

It is not a de Polignac number, because 621818993 - 2¹⁴ = 621802609 is a prime.

It is not a weakly prime, because it can be changed into another prime (621818903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310909496 + 310909497.

It is an arithmetic number, because the mean of its divisors is an integer number (310909497).

Almost surely, 2^621818993 is an apocalyptic number.

It is an amenable number.

621818993 is a deficient number, since it is larger than the sum of its proper divisors (1).

621818993 is an equidigital number, since it uses as much as digits as its factorization.

621818993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 186624, while the sum is 47.

The square root of 621818993 is about 24936.2987028949. The cubic root of 621818993 is about 853.5349867092.

The spelling of 621818993 in words is "six hundred twenty-one million, eight hundred eighteen thousand, nine hundred ninety-three".