21665086445 has 16 divisors (see below), whose sum is σ = 26445597120. Its totient is φ = 17033892864.

The previous prime is 21665086439. The next prime is 21665086451. The reversal of 21665086445 is 54468056612.

It is an interprime number because it is at equal distance from previous prime (21665086439) and next prime (21665086451).

It is a cyclic number.

It is not a de Polignac number, because 21665086445 - 2¹⁸ = 21664824301 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21665086445.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1582349 + ... + 1595981.

It is an arithmetic number, because the mean of its divisors is an integer number (1652849820).

Almost surely, 2^21665086445 is an apocalyptic number.

It is an amenable number.

21665086445 is a deficient number, since it is larger than the sum of its proper divisors (4780510675).

21665086445 is a wasteful number, since it uses less digits than its factorization.

21665086445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19084.

The product of its (nonzero) digits is 1382400, while the sum is 47.

The spelling of 21665086445 in words is "twenty-one billion, six hundred sixty-five million, eighty-six thousand, four hundred forty-five".