221151631 has 4 divisors (see below), whose sum is σ = 221754592. Its totient is φ = 220548672.

The previous prime is 221151607. The next prime is 221151643. The reversal of 221151631 is 136151122.

It is a happy number.

221151631 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 221151631 - 2⁵ = 221151599 is a prime.

It is a super-2 number, since 2×221151631² = 97816087787920322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221151661) 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, 300930 + ... + 301663.

It is an arithmetic number, because the mean of its divisors is an integer number (55438648).

Almost surely, 2^221151631 is an apocalyptic number.

221151631 is a deficient number, since it is larger than the sum of its proper divisors (602961).

221151631 is an equidigital number, since it uses as much as digits as its factorization.

221151631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 602960.

The product of its digits is 360, while the sum is 22.

The square root of 221151631 is about 14871.1677752623. The cubic root of 221151631 is about 604.7326013641.

The spelling of 221151631 in words is "two hundred twenty-one million, one hundred fifty-one thousand, six hundred thirty-one".