221020131 has 4 divisors (see below), whose sum is σ = 294693512. Its totient is φ = 147346752.

The previous prime is 221020127. The next prime is 221020157. The reversal of 221020131 is 131020122.

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

It is not a de Polignac number, because 221020131 - 2² = 221020127 is a prime.

It is a super-2 number, since 2×221020131² = 97699796614514322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221020531) 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, 36836686 + ... + 36836691.

It is an arithmetic number, because the mean of its divisors is an integer number (73673378).

Almost surely, 2^221020131 is an apocalyptic number.

221020131 is a deficient number, since it is larger than the sum of its proper divisors (73673381).

221020131 is an equidigital number, since it uses as much as digits as its factorization.

221020131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73673380.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 221020131 is about 14866.7458107011. The cubic root of 221020131 is about 604.6127166443.

Adding to 221020131 its reverse (131020122), we get a palindrome (352040253).

Subtracting from 221020131 its reverse (131020122), we obtain a palindrome (90000009).

The spelling of 221020131 in words is "two hundred twenty-one million, twenty thousand, one hundred thirty-one".