21263541620 has 12 divisors (see below), whose sum is σ = 44653437444. Its totient is φ = 8505416640.

The previous prime is 21263541493. The next prime is 21263541623. The reversal of 21263541620 is 2614536212.

It can be written as a sum of positive squares in 2 ways, for example, as 6015243364 + 15248298256 = 77558^2 + 123484^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21263541623) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 531588521 + ... + 531588560.

It is an arithmetic number, because the mean of its divisors is an integer number (3721119787).

Almost surely, 2^21263541620 is an apocalyptic number.

21263541620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21263541620 is an abundant number, since it is smaller than the sum of its proper divisors (23389895824).

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

21263541620 is a wasteful number, since it uses less digits than its factorization.

21263541620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1063177090 (or 1063177088 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The spelling of 21263541620 in words is "twenty-one billion, two hundred sixty-three million, five hundred forty-one thousand, six hundred twenty".