21506137077352 has 16 divisors (see below), whose sum is σ = 40324225146660. Its totient is φ = 10753010371584.

The previous prime is 21506137077331. The next prime is 21506137077367. The reversal of 21506137077352 is 25377073160512.

It can be written as a sum of positive squares in 2 ways, for example, as 21485208825796 + 20928251556 = 4635214^2 + 144666^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21506137077296 and 21506137077305.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5679033 + ... + 8675464.

Almost surely, 2^{21506137077352} is an apocalyptic number.

It is an amenable number.

21506137077352 is a deficient number, since it is larger than the sum of its proper divisors (18818088069308).

21506137077352 is a wasteful number, since it uses less digits than its factorization.

21506137077352 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14541780 (or 14541776 counting only the distinct ones).

The product of its (nonzero) digits is 1852200, while the sum is 49.

The spelling of 21506137077352 in words is "twenty-one trillion, five hundred six billion, one hundred thirty-seven million, seventy-seven thousand, three hundred fifty-two".