21611771154572 has 12 divisors (see below), whose sum is σ = 39040618860096. Its totient is φ = 10457308623120.

The previous prime is 21611771154569. The next prime is 21611771154577. The reversal of 21611771154572 is 27545117711612.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21611771154572.

It is not an unprimeable number, because it can be changed into a prime (21611771154577) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87144238403 + ... + 87144238650.

It is an arithmetic number, because the mean of its divisors is an integer number (3253384905008).

Almost surely, 2^{21611771154572} is an apocalyptic number.

It is an amenable number.

21611771154572 is a deficient number, since it is larger than the sum of its proper divisors (17428847705524).

21611771154572 is a wasteful number, since it uses less digits than its factorization.

21611771154572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174288477088 (or 174288477086 counting only the distinct ones).

The product of its digits is 823200, while the sum is 50.

The spelling of 21611771154572 in words is "twenty-one trillion, six hundred eleven billion, seven hundred seventy-one million, one hundred fifty-four thousand, five hundred seventy-two".