21516085397 has 8 divisors (see below), whose sum is σ = 22484896896. Its totient is φ = 20568566592.

The previous prime is 21516085387. The next prime is 21516085403. The reversal of 21516085397 is 79358061512.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21516085397 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21516085307) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5321108 + ... + 5325149.

It is an arithmetic number, because the mean of its divisors is an integer number (2810612112).

Almost surely, 2^21516085397 is an apocalyptic number.

It is an amenable number.

21516085397 is a deficient number, since it is larger than the sum of its proper divisors (968811499).

21516085397 is a wasteful number, since it uses less digits than its factorization.

21516085397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10646347.

The product of its (nonzero) digits is 453600, while the sum is 47.

The spelling of 21516085397 in words is "twenty-one billion, five hundred sixteen million, eighty-five thousand, three hundred ninety-seven".