398708621 has 2 divisors, whose sum is σ = 398708622. Its totient is φ = 398708620.

The previous prime is 398708581. The next prime is 398708689. The reversal of 398708621 is 126807893.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 397563721 + 1144900 = 19939^2 + 1070^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-398708621 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (398708221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199354310 + 199354311.

It is an arithmetic number, because the mean of its divisors is an integer number (199354311).

Almost surely, 2^398708621 is an apocalyptic number.

It is an amenable number.

398708621 is a deficient number, since it is larger than the sum of its proper divisors (1).

398708621 is an equidigital number, since it uses as much as digits as its factorization.

398708621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 44.

The square root of 398708621 is about 19967.6894256697. The cubic root of 398708621 is about 736.0125314157.

The spelling of 398708621 in words is "three hundred ninety-eight million, seven hundred eight thousand, six hundred twenty-one".