221525231 has 4 divisors (see below), whose sum is σ = 221899392. Its totient is φ = 221151072.

The previous prime is 221525191. The next prime is 221525233. The reversal of 221525231 is 132525122.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221525231 is a prime.

It is a super-2 number, since 2×221525231² = 98146855939206722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221525197 and 221525206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221525233) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 186191 + ... + 187376.

It is an arithmetic number, because the mean of its divisors is an integer number (55474848).

Almost surely, 2^221525231 is an apocalyptic number.

221525231 is a deficient number, since it is larger than the sum of its proper divisors (374161).

221525231 is an equidigital number, since it uses as much as digits as its factorization.

221525231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 374160.

The product of its digits is 1200, while the sum is 23.

The square root of 221525231 is about 14883.7236940223. The cubic root of 221525231 is about 605.0729425064.

The spelling of 221525231 in words is "two hundred twenty-one million, five hundred twenty-five thousand, two hundred thirty-one".