21651611615612 has 18 divisors (see below), whose sum is σ = 41648038046664. Its totient is φ = 9841641643240.

The previous prime is 21651611615591. The next prime is 21651611615659.

It is a happy number.

21651611615612 is nontrivially palindromic in base 10.

It is a super-3 number, since 3×21651611615612³ (a number of 41 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 22367366888 + ... + 22367367855.

Almost surely, 2^{21651611615612} is an apocalyptic number.

21651611615612 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21651611615612 is a deficient number, since it is larger than the sum of its proper divisors (19996426431052).

21651611615612 is a wasteful number, since it uses less digits than its factorization.

21651611615612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44734734769 (or 44734734756 counting only the distinct ones).

The product of its digits is 129600, while the sum is 44.

The spelling of 21651611615612 in words is "twenty-one trillion, six hundred fifty-one billion, six hundred eleven million, six hundred fifteen thousand, six hundred twelve".