221901772 has 12 divisors (see below), whose sum is σ = 388445176. Its totient is φ = 110917440.

The previous prime is 221901761. The next prime is 221901781. The reversal of 221901772 is 277109122.

It is a happy number.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12163 + ... + 24325.

Almost surely, 2^221901772 is an apocalyptic number.

221901772 is the 12163-rd pentagonal number.

It is an amenable number.

221901772 is a deficient number, since it is larger than the sum of its proper divisors (166543404).

221901772 is a wasteful number, since it uses less digits than its factorization.

221901772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16728 (or 16726 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 31.

The square root of 221901772 is about 14896.3677451921. The cubic root of 221901772 is about 605.4155758684.

The spelling of 221901772 in words is "two hundred twenty-one million, nine hundred one thousand, seven hundred seventy-two".