221375428 has 24 divisors (see below), whose sum is σ = 414191232. Its totient is φ = 103161984.

The previous prime is 221375419. The next prime is 221375507. The reversal of 221375428 is 824573122.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a junction number, because it is equal to n+sod(n) for n = 221375393 and 221375402.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8800 + ... + 22807.

It is an arithmetic number, because the mean of its divisors is an integer number (17257968).

Almost surely, 2^221375428 is an apocalyptic number.

It is an amenable number.

221375428 is a deficient number, since it is larger than the sum of its proper divisors (192815804).

221375428 is a wasteful number, since it uses less digits than its factorization.

221375428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31731 (or 31729 counting only the distinct ones).

The product of its digits is 26880, while the sum is 34.

The square root of 221375428 is about 14878.6903993598. The cubic root of 221375428 is about 604.9365213548.

The spelling of 221375428 in words is "two hundred twenty-one million, three hundred seventy-five thousand, four hundred twenty-eight".