621598561 has 2 divisors, whose sum is σ = 621598562. Its totient is φ = 621598560.

The previous prime is 621598553. The next prime is 621598619. The reversal of 621598561 is 165895126.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 612265536 + 9333025 = 24744^2 + 3055^2 .

It is a cyclic number.

It is not a de Polignac number, because 621598561 - 2³ = 621598553 is a prime.

It is not a weakly prime, because it can be changed into another prime (621598361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310799280 + 310799281.

It is an arithmetic number, because the mean of its divisors is an integer number (310799281).

Almost surely, 2^621598561 is an apocalyptic number.

It is an amenable number.

621598561 is a deficient number, since it is larger than the sum of its proper divisors (1).

621598561 is an equidigital number, since it uses as much as digits as its factorization.

621598561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 129600, while the sum is 43.

The square root of 621598561 is about 24931.8784089767. The cubic root of 621598561 is about 853.4341167009.

The spelling of 621598561 in words is "six hundred twenty-one million, five hundred ninety-eight thousand, five hundred sixty-one".