309055221 has 24 divisors (see below), whose sum is σ = 460162560. Its totient is φ = 199773216.

The previous prime is 309055211. The next prime is 309055237. The reversal of 309055221 is 122550903.

309055221 is a `hidden beast` number, since 3 + 0 + 90 + 552 + 21 = 666.

It is not a de Polignac number, because 309055221 - 2²⁵ = 275500789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (309055211) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42756 + ... + 49458.

It is an arithmetic number, because the mean of its divisors is an integer number (19173440).

Almost surely, 2^309055221 is an apocalyptic number.

It is an amenable number.

309055221 is a deficient number, since it is larger than the sum of its proper divisors (151107339).

309055221 is a wasteful number, since it uses less digits than its factorization.

309055221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6865 (or 6862 counting only the distinct ones).

The product of its (nonzero) digits is 2700, while the sum is 27.

The square root of 309055221 is about 17579.9664675448. The cubic root of 309055221 is about 676.1017004710.

It can be divided in two parts, 3090 and 55221, that added together give a triangular number (58311 = T₃₄₁).

The spelling of 309055221 in words is "three hundred nine million, fifty-five thousand, two hundred twenty-one".