21137540840505 has 24 divisors (see below), whose sum is σ = 36638688864960. Its totient is φ = 11273267502240.

The previous prime is 21137540840489. The next prime is 21137540840509. The reversal of 21137540840505 is 50504804573112.

21137540840505 is a `hidden beast` number, since 2 + 1 + 13 + 7 + 54 + 0 + 84 + 0 + 505 = 666.

It is not a de Polignac number, because 21137540840505 - 2⁴ = 21137540840489 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (21137540840509) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4251670 + ... + 7768640.

It is an arithmetic number, because the mean of its divisors is an integer number (1526612036040).

Almost surely, 2^{21137540840505} is an apocalyptic number.

It is an amenable number.

21137540840505 is a deficient number, since it is larger than the sum of its proper divisors (15501148024455).

21137540840505 is a wasteful number, since it uses less digits than its factorization.

21137540840505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3650541 (or 3650538 counting only the distinct ones).

The product of its (nonzero) digits is 672000, while the sum is 45.

The spelling of 21137540840505 in words is "twenty-one trillion, one hundred thirty-seven billion, five hundred forty million, eight hundred forty thousand, five hundred five".