21595521887 has 2 divisors, whose sum is σ = 21595521888. Its totient is φ = 21595521886.

The previous prime is 21595521841. The next prime is 21595521911. The reversal of 21595521887 is 78812559512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21595521887 - 2⁸ = 21595521631 is a prime.

It is a super-3 number, since 3×21595521887³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21595521817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10797760943 + 10797760944.

It is an arithmetic number, because the mean of its divisors is an integer number (10797760944).

Almost surely, 2^21595521887 is an apocalyptic number.

21595521887 is a deficient number, since it is larger than the sum of its proper divisors (1).

21595521887 is an equidigital number, since it uses as much as digits as its factorization.

21595521887 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2016000, while the sum is 53.

The spelling of 21595521887 in words is "twenty-one billion, five hundred ninety-five million, five hundred twenty-one thousand, eight hundred eighty-seven".