21573361187 has 16 divisors (see below), whose sum is σ = 25477330944. Its totient is φ = 17894781000.

The previous prime is 21573361177. The next prime is 21573361207. The reversal of 21573361187 is 78116337512.

It is not a de Polignac number, because 21573361187 - 2⁴ = 21573361171 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21573361127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 156812 + ... + 260262.

It is an arithmetic number, because the mean of its divisors is an integer number (1592333184).

Almost surely, 2^21573361187 is an apocalyptic number.

21573361187 is a deficient number, since it is larger than the sum of its proper divisors (3903969757).

21573361187 is an frugal number, since it uses more digits than its factorization.

21573361187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103551 (or 103489 counting only the distinct ones).

The product of its digits is 211680, while the sum is 44.

Adding to 21573361187 its reverse (78116337512), we get a palindrome (99689698699).

The spelling of 21573361187 in words is "twenty-one billion, five hundred seventy-three million, three hundred sixty-one thousand, one hundred eighty-seven".