21374374231665 has 192 divisors, whose sum is σ = 47423886182400. Its totient is φ = 8664655214592.

The previous prime is 21374374231643. The next prime is 21374374231673. The reversal of 21374374231665 is 56613247347312.

21374374231665 is a `hidden beast` number, since 2 + 1 + 3 + 7 + 437 + 42 + 3 + 166 + 5 = 666.

It is not a de Polignac number, because 21374374231665 - 2¹⁶ = 21374374166129 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 11076831 + ... + 12862539.

It is an arithmetic number, because the mean of its divisors is an integer number (246999407200).

Almost surely, 2^{21374374231665} is an apocalyptic number.

It is an amenable number.

21374374231665 is an abundant number, since it is smaller than the sum of its proper divisors (26049511950735).

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

21374374231665 is a wasteful number, since it uses less digits than its factorization.

21374374231665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1785856 (or 1785853 counting only the distinct ones).

The product of its digits is 15240960, while the sum is 54.

The spelling of 21374374231665 in words is "twenty-one trillion, three hundred seventy-four billion, three hundred seventy-four million, two hundred thirty-one thousand, six hundred sixty-five".