221021131 has 8 divisors (see below), whose sum is σ = 234837360. Its totient is φ = 208015264.

The previous prime is 221021111. The next prime is 221021137. The reversal of 221021131 is 131120122.

221021131 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 221021131 - 2¹⁵ = 220988363 is a prime.

It is a super-2 number, since 2×221021131² = 97700680697038322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221021137) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17581 + ... + 27406.

It is an arithmetic number, because the mean of its divisors is an integer number (29354670).

Almost surely, 2^221021131 is an apocalyptic number.

221021131 is a deficient number, since it is larger than the sum of its proper divisors (13816229).

221021131 is an frugal number, since it uses more digits than its factorization.

221021131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45038 (or 45004 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 221021131 is about 14866.7794427711. The cubic root of 221021131 is about 604.6136284945.

Adding to 221021131 its reverse (131120122), we get a palindrome (352141253).

The spelling of 221021131 in words is "two hundred twenty-one million, twenty-one thousand, one hundred thirty-one".