220172890921 has 4 divisors (see below), whose sum is σ = 221853600144. Its totient is φ = 218492181700.

The previous prime is 220172890909. The next prime is 220172890969. The reversal of 220172890921 is 129098271022.

It is a happy number.

220172890921 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 220172890921 - 2⁷ = 220172890793 is a prime.

It is a super-2 number, since 2×220172890921² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (220172890991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 840354415 + ... + 840354676.

It is an arithmetic number, because the mean of its divisors is an integer number (55463400036).

Almost surely, 2^220172890921 is an apocalyptic number.

It is an amenable number.

220172890921 is a deficient number, since it is larger than the sum of its proper divisors (1680709223).

220172890921 is a wasteful number, since it uses less digits than its factorization.

220172890921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1680709222.

The product of its (nonzero) digits is 72576, while the sum is 43.

The spelling of 220172890921 in words is "two hundred twenty billion, one hundred seventy-two million, eight hundred ninety thousand, nine hundred twenty-one".