21715021531161 has 24 divisors (see below), whose sum is σ = 35848197041280. Its totient is φ = 12408176180736.

The previous prime is 21715021531153. The next prime is 21715021531163. The reversal of 21715021531161 is 16113512051712.

21715021531161 is a `hidden beast` number, since 2 + 1 + 71 + 5 + 0 + 215 + 311 + 61 = 666.

It is not a de Polignac number, because 21715021531161 - 2³ = 21715021531153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21715021531163) 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, 3721845 + ... + 7568498.

It is an arithmetic number, because the mean of its divisors is an integer number (1493674876720).

Almost surely, 2^{21715021531161} is an apocalyptic number.

21715021531161 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21715021531161 is a deficient number, since it is larger than the sum of its proper divisors (14133175510119).

21715021531161 is a wasteful number, since it uses less digits than its factorization.

21715021531161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11320885 (or 11320882 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 36.

Adding to 21715021531161 its reverse (16113512051712), we get a palindrome (37828533582873).

The spelling of 21715021531161 in words is "twenty-one trillion, seven hundred fifteen billion, twenty-one million, five hundred thirty-one thousand, one hundred sixty-one".