221665137405231 has 16 divisors (see below), whose sum is σ = 320241092022656. Its totient is φ = 135572448357216.

The previous prime is 221665137405211. The next prime is 221665137405247. The reversal of 221665137405231 is 132504731566122.

It is not a de Polignac number, because 221665137405231 - 2³⁰ = 221664063663407 is a prime.

It is a super-2 number, since 2×221665137405231² (a number of 29 digits) 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 (221665137405211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17434722085 + ... + 17434734798.

It is an arithmetic number, because the mean of its divisors is an integer number (20015068251416).

Almost surely, 2^{221665137405231} is an apocalyptic number.

221665137405231 is a deficient number, since it is larger than the sum of its proper divisors (98575954617425).

221665137405231 is a wasteful number, since it uses less digits than its factorization.

221665137405231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34869457062.

The product of its (nonzero) digits is 1814400, while the sum is 48.

The spelling of 221665137405231 in words is "two hundred twenty-one trillion, six hundred sixty-five billion, one hundred thirty-seven million, four hundred five thousand, two hundred thirty-one".