21885236840 has 16 divisors (see below), whose sum is σ = 49241782980. Its totient is φ = 8754094720.

The previous prime is 21885236809. The next prime is 21885236843. The reversal of 21885236840 is 4863258812.

It can be written as a sum of positive squares in 2 ways, for example, as 18342368356 + 3542868484 = 135434^2 + 59522^2 .

It is not an unprimeable number, because it can be changed into a prime (21885236843) 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, 273565421 + ... + 273565500.

Almost surely, 2^21885236840 is an apocalyptic number.

21885236840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21885236840 is an abundant number, since it is smaller than the sum of its proper divisors (27356546140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21885236840 is a wasteful number, since it uses less digits than its factorization.

21885236840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 547130932 (or 547130928 counting only the distinct ones).

The product of its (nonzero) digits is 737280, while the sum is 47.

The spelling of 21885236840 in words is "twenty-one billion, eight hundred eighty-five million, two hundred thirty-six thousand, eight hundred forty".