21226015620 has 72 divisors (see below), whose sum is σ = 64399719384. Its totient is φ = 5659027968.

The previous prime is 21226015537. The next prime is 21226015631. The reversal of 21226015620 is 2651062212.

21226015620 is a `hidden beast` number, since 2 + 1 + 2 + 2 + 601 + 56 + 2 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 10466517636 + 10759497984 = 102306^2 + 103728^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1051462 + ... + 1071458.

It is an arithmetic number, because the mean of its divisors is an integer number (894440547).

Almost surely, 2^21226015620 is an apocalyptic number.

21226015620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21226015620 is an abundant number, since it is smaller than the sum of its proper divisors (43173703764).

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

21226015620 is a wasteful number, since it uses less digits than its factorization.

21226015620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25909 (or 25904 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

Adding to 21226015620 its reverse (2651062212), we get a palindrome (23877077832).

The spelling of 21226015620 in words is "twenty-one billion, two hundred twenty-six million, fifteen thousand, six hundred twenty".