21515410133540 has 24 divisors (see below), whose sum is σ = 46740373739640. Its totient is φ = 8309399775488.

The previous prime is 21515410133533. The next prime is 21515410133563. The reversal of 21515410133540 is 4533101451512.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 4669376443876 + 16846033689664 = 2160874^2 + 4104392^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21515410133540.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18547766777 + ... + 18547767936.

It is an arithmetic number, because the mean of its divisors is an integer number (1947515572485).

Almost surely, 2^{21515410133540} is an apocalyptic number.

21515410133540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21515410133540 is an abundant number, since it is smaller than the sum of its proper divisors (25224963606100).

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

21515410133540 is a wasteful number, since it uses less digits than its factorization.

21515410133540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37095534751 (or 37095534749 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 35.

The spelling of 21515410133540 in words is "twenty-one trillion, five hundred fifteen billion, four hundred ten million, one hundred thirty-three thousand, five hundred forty".