21611666151 has 24 divisors (see below), whose sum is σ = 32325631104. Its totient is φ = 13898969280.

The previous prime is 21611666137. The next prime is 21611666159. The reversal of 21611666151 is 15166611612.

It is not a de Polignac number, because 21611666151 - 2⁷ = 21611666023 is a prime.

It is a super-2 number, since 2×21611666151² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21611666159) 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, 33736 + ... + 210621.

It is an arithmetic number, because the mean of its divisors is an integer number (1346901296).

Almost surely, 2^21611666151 is an apocalyptic number.

21611666151 is a deficient number, since it is larger than the sum of its proper divisors (10713964953).

21611666151 is a wasteful number, since it uses less digits than its factorization.

21611666151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244711 (or 244708 counting only the distinct ones).

The product of its digits is 12960, while the sum is 36.

The spelling of 21611666151 in words is "twenty-one billion, six hundred eleven million, six hundred sixty-six thousand, one hundred fifty-one".