21221210031 has 16 divisors (see below), whose sum is σ = 32997024000. Its totient is φ = 12126405144.

The previous prime is 21221209957. The next prime is 21221210033. The reversal of 21221210031 is 13001212212.

It is not a de Polignac number, because 21221210031 - 2¹⁰ = 21221209007 is a prime.

It is a super-2 number, since 2×21221210031² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221210033) 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, 10310541 + ... + 10312598.

It is an arithmetic number, because the mean of its divisors is an integer number (2062314000).

Almost surely, 2^21221210031 is an apocalyptic number.

21221210031 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21221210031 is a deficient number, since it is larger than the sum of its proper divisors (11775813969).

21221210031 is an equidigital number, since it uses as much as digits as its factorization.

21221210031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20623163 (or 20623149 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21221210031 its reverse (13001212212), we get a palindrome (34222422243).

The spelling of 21221210031 in words is "twenty-one billion, two hundred twenty-one million, two hundred ten thousand, thirty-one".