21888901 has 4 divisors (see below), whose sum is σ = 22048812. Its totient is φ = 21728992.

The previous prime is 21888899. The next prime is 21888907. The reversal of 21888901 is 10988812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17892900 + 3996001 = 4230^2 + 1999^2 .

It is a cyclic number.

It is not a de Polignac number, because 21888901 - 2¹ = 21888899 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21888907) 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, 79750 + ... + 80023.

It is an arithmetic number, because the mean of its divisors is an integer number (5512203).

Almost surely, 2^21888901 is an apocalyptic number.

It is an amenable number.

21888901 is a deficient number, since it is larger than the sum of its proper divisors (159911).

21888901 is a wasteful number, since it uses less digits than its factorization.

21888901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159910.

The product of its (nonzero) digits is 9216, while the sum is 37.

The square root of 21888901 is about 4678.5575768606. The cubic root of 21888901 is about 279.7314644807.

The spelling of 21888901 in words is "twenty-one million, eight hundred eighty-eight thousand, nine hundred one".