621778057 has 2 divisors, whose sum is σ = 621778058. Its totient is φ = 621778056.

The previous prime is 621777913. The next prime is 621778061. The reversal of 621778057 is 750877126.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 356869881 + 264908176 = 18891^2 + 16276^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621778057 is a prime.

It is not a weakly prime, because it can be changed into another prime (621778657) 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, 310889028 + 310889029.

It is an arithmetic number, because the mean of its divisors is an integer number (310889029).

Almost surely, 2^621778057 is an apocalyptic number.

It is an amenable number.

621778057 is a deficient number, since it is larger than the sum of its proper divisors (1).

621778057 is an equidigital number, since it uses as much as digits as its factorization.

621778057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 164640, while the sum is 43.

The square root of 621778057 is about 24935.4778779152. The cubic root of 621778057 is about 853.5162561379.

The spelling of 621778057 in words is "six hundred twenty-one million, seven hundred seventy-eight thousand, fifty-seven".