221020031 has 4 divisors (see below), whose sum is σ = 221612952. Its totient is φ = 220427112.

The previous prime is 221020003. The next prime is 221020039. The reversal of 221020031 is 130020122.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 221020031 - 2¹⁴ = 221003647 is a prime.

It is a super-2 number, since 2×221020031² = 97699708206481922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221019994 and 221020021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221020039) 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, 295901 + ... + 296646.

It is an arithmetic number, because the mean of its divisors is an integer number (55403238).

Almost surely, 2^221020031 is an apocalyptic number.

221020031 is a deficient number, since it is larger than the sum of its proper divisors (592921).

221020031 is an equidigital number, since it uses as much as digits as its factorization.

221020031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592920.

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 221020031 is about 14866.7424474900. The cubic root of 221020031 is about 604.6126254591.

Adding to 221020031 its reverse (130020122), we get a palindrome (351040153).

Subtracting from 221020031 its reverse (130020122), we obtain a palindrome (90999909).

The spelling of 221020031 in words is "two hundred twenty-one million, twenty thousand, thirty-one".