21072211171 has 16 divisors (see below), whose sum is σ = 23520647808. Its totient is φ = 18717480000.

The previous prime is 21072211169. The next prime is 21072211213. The reversal of 21072211171 is 17111227012.

It is a cyclic number.

It is not a de Polignac number, because 21072211171 - 2¹ = 21072211169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21072211141) 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, 36705 + ... + 208546.

It is an arithmetic number, because the mean of its divisors is an integer number (1470040488).

Almost surely, 2^21072211171 is an apocalyptic number.

21072211171 is a deficient number, since it is larger than the sum of its proper divisors (2448436637).

21072211171 is a wasteful number, since it uses less digits than its factorization.

21072211171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245442.

The product of its (nonzero) digits is 392, while the sum is 25.

Adding to 21072211171 its reverse (17111227012), we get a palindrome (38183438183).

The spelling of 21072211171 in words is "twenty-one billion, seventy-two million, two hundred eleven thousand, one hundred seventy-one".