21213444531356 has 96 divisors (see below), whose sum is σ = 46412098854912. Its totient is φ = 8242113378240.

The previous prime is 21213444531353. The next prime is 21213444531373. The reversal of 21213444531356 is 65313544431212.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213444531353) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 163939475 + ... + 164068821.

It is an arithmetic number, because the mean of its divisors is an integer number (483459363072).

Almost surely, 2^{21213444531356} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21213444531356, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23206049427456).

21213444531356 is an abundant number, since it is smaller than the sum of its proper divisors (25198654323556).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21213444531356 is a wasteful number, since it uses less digits than its factorization.

21213444531356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130839 (or 130837 counting only the distinct ones).

The product of its digits is 1036800, while the sum is 44.

Adding to 21213444531356 its reverse (65313544431212), we get a palindrome (86526988962568).

The spelling of 21213444531356 in words is "twenty-one trillion, two hundred thirteen billion, four hundred forty-four million, five hundred thirty-one thousand, three hundred fifty-six".