21611611611612 has 72 divisors (see below), whose sum is σ = 61049208899952. Its totient is φ = 6389242156800.

The previous prime is 21611611611599. The next prime is 21611611611643.

21611611611612 is a `hidden beast` number, since 2 + 1 + 6 + 1 + 16 + 1 + 16 + 11 + 612 = 666.

21611611611612 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 665529823 + ... + 665562294.

It is an arithmetic number, because the mean of its divisors is an integer number (847905679166).

Almost surely, 2^{21611611611612} is an apocalyptic number.

21611611611612 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21611611611612 is an abundant number, since it is smaller than the sum of its proper divisors (39437597288340).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21611611611612 is a wasteful number, since it uses less digits than its factorization.

21611611611612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1331092179 (or 1331092174 counting only the distinct ones).

The product of its digits is 5184, while the sum is 36.

It can be divided in two parts, 2161161 and 1611612, that added together give a palindrome (3772773).

The spelling of 21611611611612 in words is "twenty-one trillion, six hundred eleven billion, six hundred eleven million, six hundred eleven thousand, six hundred twelve".