398057221 has 6 divisors (see below), whose sum is σ = 403166022. Its totient is φ = 393012360.

The previous prime is 398057167. The next prime is 398057237. The reversal of 398057221 is 122750893.

It can be written as a sum of positive squares in only one way, i.e., 341732196 + 56325025 = 18486^2 + 7505^2 .

It is not a de Polignac number, because 398057221 - 2²⁷ = 263839493 is a prime.

It is a pancake number, because a pancake can be divided into 398057221 parts by 28215 straight cuts.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398037221) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 25650 + ... + 38131.

It is an arithmetic number, because the mean of its divisors is an integer number (67194337).

Almost surely, 2^398057221 is an apocalyptic number.

It is an amenable number.

398057221 is a deficient number, since it is larger than the sum of its proper divisors (5108801).

398057221 is an frugal number, since it uses more digits than its factorization.

398057221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63939 (or 63860 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 398057221 is about 19951.3714064973. The cubic root of 398057221 is about 735.6114867487.

It can be divided in two parts, 398057 and 221, that added together give a triangular number (398278 = T₈₉₂).

The spelling of 398057221 in words is "three hundred ninety-eight million, fifty-seven thousand, two hundred twenty-one".