21149904168 has 160 divisors (see below), whose sum is σ = 60533589600. Its totient is φ = 6897115008.

The previous prime is 21149904157. The next prime is 21149904257. The reversal of 21149904168 is 86140994112.

It is a happy number.

21149904168 is a `hidden beast` number, since 2 + 1 + 149 + 90 + 416 + 8 = 666.

It is an unprimeable number.

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 39 ways as a sum of consecutive naturals, for example, 8677446 + ... + 8679882.

It is an arithmetic number, because the mean of its divisors is an integer number (378334935).

Almost surely, 2^21149904168 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21149904168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30266794800).

21149904168 is an abundant number, since it is smaller than the sum of its proper divisors (39383685432).

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

21149904168 is a wasteful number, since it uses less digits than its factorization.

21149904168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2741 (or 2728 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The spelling of 21149904168 in words is "twenty-one billion, one hundred forty-nine million, nine hundred four thousand, one hundred sixty-eight".