398950921 has 4 divisors (see below), whose sum is σ = 398991892. Its totient is φ = 398909952.

The previous prime is 398950901. The next prime is 398950933. The reversal of 398950921 is 129059893.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 147379600 + 251571321 = 12140^2 + 15861^2 .

It is a cyclic number.

It is not a de Polignac number, because 398950921 - 2⁷ = 398950793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (398950901) 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 in 3 ways as a sum of consecutive naturals, for example, 3421 + ... + 28453.

It is an arithmetic number, because the mean of its divisors is an integer number (99747973).

Almost surely, 2^398950921 is an apocalyptic number.

It is an amenable number.

398950921 is a deficient number, since it is larger than the sum of its proper divisors (40971).

398950921 is a wasteful number, since it uses less digits than its factorization.

398950921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40970.

The product of its (nonzero) digits is 174960, while the sum is 46.

The square root of 398950921 is about 19973.7558060571. The cubic root of 398950921 is about 736.1615957646.

The spelling of 398950921 in words is "three hundred ninety-eight million, nine hundred fifty thousand, nine hundred twenty-one".