621998401 has 2 divisors, whose sum is σ = 621998402. Its totient is φ = 621998400.

The previous prime is 621998371. The next prime is 621998519. The reversal of 621998401 is 104899126.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 490666801 + 131331600 = 22151^2 + 11460^2 .

It is a cyclic number.

It is not a de Polignac number, because 621998401 - 2⁵ = 621998369 is a prime.

It is not a weakly prime, because it can be changed into another prime (621993401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310999200 + 310999201.

It is an arithmetic number, because the mean of its divisors is an integer number (310999201).

Almost surely, 2^621998401 is an apocalyptic number.

It is an amenable number.

621998401 is a deficient number, since it is larger than the sum of its proper divisors (1).

621998401 is an equidigital number, since it uses as much as digits as its factorization.

621998401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 621998401 is about 24939.8957696298. The cubic root of 621998401 is about 853.6170664794.

The spelling of 621998401 in words is "six hundred twenty-one million, nine hundred ninety-eight thousand, four hundred one".