21801021168 has 40 divisors (see below), whose sum is σ = 56762779648. Its totient is φ = 7209784512.

The previous prime is 21801021163. The next prime is 21801021191. The reversal of 21801021168 is 86112010812.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21801021161) 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 7 ways as a sum of consecutive naturals, for example, 1782046 + ... + 1794237.

Almost surely, 2^21801021168 is an apocalyptic number.

It is an amenable number.

21801021168 is an abundant number, since it is smaller than the sum of its proper divisors (34961758480).

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

21801021168 is a wasteful number, since it uses less digits than its factorization.

21801021168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3576421 (or 3576415 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 30.

The spelling of 21801021168 in words is "twenty-one billion, eight hundred one million, twenty-one thousand, one hundred sixty-eight".