221210031 has 16 divisors (see below), whose sum is σ = 337722368. Its totient is φ = 126165600.

The previous prime is 221210009. The next prime is 221210051. The reversal of 221210031 is 130012122.

It is not a de Polignac number, because 221210031 - 2⁷ = 221209903 is a prime.

It is a super-2 number, since 2×221210031² = 97867755630041922, 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 = 221209989 and 221210016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221210051) 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, 1626 + ... + 21096.

It is an arithmetic number, because the mean of its divisors is an integer number (21107648).

Almost surely, 2^221210031 is an apocalyptic number.

221210031 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

221210031 is a deficient number, since it is larger than the sum of its proper divisors (116512337).

221210031 is a wasteful number, since it uses less digits than its factorization.

221210031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20022.

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

The square root of 221210031 is about 14873.1311767227. The cubic root of 221210031 is about 604.7858277041.

Adding to 221210031 its reverse (130012122), we get a palindrome (351222153).

The spelling of 221210031 in words is "two hundred twenty-one million, two hundred ten thousand, thirty-one".