21659379451665 has 32 divisors (see below), whose sum is σ = 35406345547776. Its totient is φ = 11303714903040.

The previous prime is 21659379451637. The next prime is 21659379451729. The reversal of 21659379451665 is 56615497395612.

It is not a de Polignac number, because 21659379451665 - 2⁹ = 21659379451153 is a prime.

It is a super-3 number, since 3×21659379451665³ (a number of 41 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21659379451665.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 77735956 + ... + 78014085.

It is an arithmetic number, because the mean of its divisors is an integer number (1106448298368).

Almost surely, 2^{21659379451665} is an apocalyptic number.

It is an amenable number.

21659379451665 is a deficient number, since it is larger than the sum of its proper divisors (13746966096111).

21659379451665 is a wasteful number, since it uses less digits than its factorization.

21659379451665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155750249.

The product of its digits is 367416000, while the sum is 69.

The spelling of 21659379451665 in words is "twenty-one trillion, six hundred fifty-nine billion, three hundred seventy-nine million, four hundred fifty-one thousand, six hundred sixty-five".