21021031213 has 24 divisors (see below), whose sum is σ = 26946493728. Its totient is φ = 16245212256.

The previous prime is 21021031193. The next prime is 21021031219. The reversal of 21021031213 is 31213012012.

It is not a de Polignac number, because 21021031213 - 2⁵ = 21021031181 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021031219) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 356331 + ... + 411112.

It is an arithmetic number, because the mean of its divisors is an integer number (1122770572).

Almost surely, 2^21021031213 is an apocalyptic number.

It is an amenable number.

21021031213 is a deficient number, since it is larger than the sum of its proper divisors (5925462515).

21021031213 is a wasteful number, since it uses less digits than its factorization.

21021031213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 767513 (or 767506 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21021031213 its reverse (31213012012), we get a palindrome (52234043225).

The spelling of 21021031213 in words is "twenty-one billion, twenty-one million, thirty-one thousand, two hundred thirteen".