21158698824 has 40 divisors (see below), whose sum is σ = 59263949910. Its totient is φ = 7052899392.

The previous prime is 21158698823. The next prime is 21158698963. The reversal of 21158698824 is 42889685112.

It can be written as a sum of positive squares in only one way, i.e., 12394368900 + 8764329924 = 111330^2 + 93618^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (21158698823) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 16325509 + ... + 16326804.

Almost surely, 2^21158698824 is an apocalyptic number.

21158698824 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21158698824 is an abundant number, since it is smaller than the sum of its proper divisors (38105251086).

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

21158698824 is a wasteful number, since it uses less digits than its factorization.

21158698824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32652331 (or 32652318 counting only the distinct ones).

The product of its digits is 2211840, while the sum is 54.

The spelling of 21158698824 in words is "twenty-one billion, one hundred fifty-eight million, six hundred ninety-eight thousand, eight hundred twenty-four".