21205436880371 has 16 divisors (see below), whose sum is σ = 21694587125760. Its totient is φ = 20717889712800.

The previous prime is 21205436880361. The next prime is 21205436880379. The reversal of 21205436880371 is 17308863450212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21205436880371 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21205436880379) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 94406846 + ... + 94631196.

It is an arithmetic number, because the mean of its divisors is an integer number (1355911695360).

Almost surely, 2^{21205436880371} is an apocalyptic number.

21205436880371 is a deficient number, since it is larger than the sum of its proper divisors (489150245389).

21205436880371 is a wasteful number, since it uses less digits than its factorization.

21205436880371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227914.

The product of its (nonzero) digits is 1935360, while the sum is 50.

The spelling of 21205436880371 in words is "twenty-one trillion, two hundred five billion, four hundred thirty-six million, eight hundred eighty thousand, three hundred seventy-one".