21231043213220 has 48 divisors (see below), whose sum is σ = 44915592073968. Its totient is φ = 8429642833920.

The previous prime is 21231043213217. The next prime is 21231043213231. The reversal of 21231043213220 is 2231234013212.

It can be written as a sum of positive squares in 8 ways, for example, as 468877084516 + 20762166128704 = 684746^2 + 4556552^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21231043213220.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2837741 + ... + 7107380.

It is an arithmetic number, because the mean of its divisors is an integer number (935741501541).

Almost surely, 2^{21231043213220} is an apocalyptic number.

21231043213220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21231043213220 is an abundant number, since it is smaller than the sum of its proper divisors (23684548860748).

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

21231043213220 is a wasteful number, since it uses less digits than its factorization.

21231043213220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9945920 (or 9945918 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 26.

Adding to 21231043213220 its reverse (2231234013212), we get a palindrome (23462277226432).

The spelling of 21231043213220 in words is "twenty-one trillion, two hundred thirty-one billion, forty-three million, two hundred thirteen thousand, two hundred twenty".