21985853187 has 16 divisors (see below), whose sum is σ = 29407339008. Its totient is φ = 14610876000.

The previous prime is 21985853179. The next prime is 21985853191. The reversal of 21985853187 is 78135858912.

It is not a de Polignac number, because 21985853187 - 2³ = 21985853179 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21985853107) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1259773 + ... + 1277105.

It is an arithmetic number, because the mean of its divisors is an integer number (1837958688).

Almost surely, 2^21985853187 is an apocalyptic number.

21985853187 is a deficient number, since it is larger than the sum of its proper divisors (7421485821).

21985853187 is a wasteful number, since it uses less digits than its factorization.

21985853187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18650.

The product of its digits is 4838400, while the sum is 57.

The spelling of 21985853187 in words is "twenty-one billion, nine hundred eighty-five million, eight hundred fifty-three thousand, one hundred eighty-seven".