21587897983 has 4 divisors (see below), whose sum is σ = 22724103160. Its totient is φ = 20451692808.

The previous prime is 21587897959. The next prime is 21587898019. The reversal of 21587897983 is 38979878512.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21587897983 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 (21587897923) 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, 568102560 + ... + 568102597.

It is an arithmetic number, because the mean of its divisors is an integer number (5681025790).

Almost surely, 2^21587897983 is an apocalyptic number.

21587897983 is a deficient number, since it is larger than the sum of its proper divisors (1136205177).

21587897983 is a wasteful number, since it uses less digits than its factorization.

21587897983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1136205176.

The product of its digits is 60963840, while the sum is 67.

The spelling of 21587897983 in words is "twenty-one billion, five hundred eighty-seven million, eight hundred ninety-seven thousand, nine hundred eighty-three".