21163751205 has 16 divisors (see below), whose sum is σ = 33874925760. Its totient is φ = 11283026048.

The previous prime is 21163751177. The next prime is 21163751227. The reversal of 21163751205 is 50215736112.

It is a cyclic number.

It is not a de Polignac number, because 21163751205 - 2⁹ = 21163750693 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 228435 + ... + 307424.

It is an arithmetic number, because the mean of its divisors is an integer number (2117182860).

Almost surely, 2^21163751205 is an apocalyptic number.

It is an amenable number.

21163751205 is a deficient number, since it is larger than the sum of its proper divisors (12711174555).

21163751205 is a wasteful number, since it uses less digits than its factorization.

21163751205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538500.

The product of its (nonzero) digits is 12600, while the sum is 33.

The spelling of 21163751205 in words is "twenty-one billion, one hundred sixty-three million, seven hundred fifty-one thousand, two hundred five".