21515514983 has 4 divisors (see below), whose sum is σ = 21528659880. Its totient is φ = 21502370088.

The previous prime is 21515514929. The next prime is 21515514997. The reversal of 21515514983 is 38941551512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21515514983 - 2⁶ = 21515514919 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21515514283) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6569993 + ... + 6573266.

It is an arithmetic number, because the mean of its divisors is an integer number (5382164970).

Almost surely, 2^21515514983 is an apocalyptic number.

21515514983 is a deficient number, since it is larger than the sum of its proper divisors (13144897).

21515514983 is a wasteful number, since it uses less digits than its factorization.

21515514983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13144896.

The product of its digits is 216000, while the sum is 44.

The spelling of 21515514983 in words is "twenty-one billion, five hundred fifteen million, five hundred fourteen thousand, nine hundred eighty-three".