21516383165 has 8 divisors (see below), whose sum is σ = 25828036920. Its totient is φ = 17207521792.

The previous prime is 21516383131. The next prime is 21516383219. The reversal of 21516383165 is 56138361512.

It can be written as a sum of positive squares in 4 ways, for example, as 7129100356 + 14387282809 = 84434^2 + 119947^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21516383165 - 2⁶ = 21516383101 is a prime.

It is a super-3 number, since 3×21516383165³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 681104 + ... + 711993.

It is an arithmetic number, because the mean of its divisors is an integer number (3228504615).

Almost surely, 2^21516383165 is an apocalyptic number.

It is an amenable number.

21516383165 is a deficient number, since it is larger than the sum of its proper divisors (4311653755).

21516383165 is a wasteful number, since it uses less digits than its factorization.

21516383165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1396191.

The product of its digits is 129600, while the sum is 41.

The spelling of 21516383165 in words is "twenty-one billion, five hundred sixteen million, three hundred eighty-three thousand, one hundred sixty-five".