21151318188 has 96 divisors (see below), whose sum is σ = 66264307200. Its totient is φ = 5071242240.

The previous prime is 21151318183. The next prime is 21151318207. The reversal of 21151318188 is 88181315112.

It is a super-2 number, since 2×21151318188² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (21151318183) 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 in 31 ways as a sum of consecutive naturals, for example, 868413 + ... + 892436.

It is an arithmetic number, because the mean of its divisors is an integer number (690253200).

Almost surely, 2^21151318188 is an apocalyptic number.

21151318188 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21151318188 is an abundant number, since it is smaller than the sum of its proper divisors (45112989012).

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

21151318188 is a wasteful number, since it uses less digits than its factorization.

21151318188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1760887 (or 1760885 counting only the distinct ones).

The product of its digits is 15360, while the sum is 39.

The spelling of 21151318188 in words is "twenty-one billion, one hundred fifty-one million, three hundred eighteen thousand, one hundred eighty-eight".