221131597 has 4 divisors (see below), whose sum is σ = 234139356. Its totient is φ = 208123840.

The previous prime is 221131577. The next prime is 221131639. The reversal of 221131597 is 795131122.

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

It can be written as a sum of positive squares in 2 ways, for example, as 124679556 + 96452041 = 11166^2 + 9821^2 .

It is a cyclic number.

It is not a de Polignac number, because 221131597 - 2²³ = 212742989 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221131577) 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, 6503854 + ... + 6503887.

It is an arithmetic number, because the mean of its divisors is an integer number (58534839).

Almost surely, 2^221131597 is an apocalyptic number.

It is an amenable number.

221131597 is a deficient number, since it is larger than the sum of its proper divisors (13007759).

221131597 is a wasteful number, since it uses less digits than its factorization.

221131597 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13007758.

The product of its digits is 3780, while the sum is 31.

The square root of 221131597 is about 14870.4941747072. The cubic root of 221131597 is about 604.7143400190.

The spelling of 221131597 in words is "two hundred twenty-one million, one hundred thirty-one thousand, five hundred ninety-seven".