21089401 has 4 divisors (see below), whose sum is σ = 22329972. Its totient is φ = 19848832.

The previous prime is 21089381. The next prime is 21089407. The reversal of 21089401 is 10498012.

It is a happy number.

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 8415801 + 12673600 = 2901^2 + 3560^2 .

It is a cyclic number.

It is not a de Polignac number, because 21089401 - 2⁷ = 21089273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21089407) 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, 620260 + ... + 620293.

It is an arithmetic number, because the mean of its divisors is an integer number (5582493).

Almost surely, 2^21089401 is an apocalyptic number.

It is an amenable number.

21089401 is a deficient number, since it is larger than the sum of its proper divisors (1240571).

21089401 is a wasteful number, since it uses less digits than its factorization.

21089401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1240570.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 21089401 is about 4592.3197841614. The cubic root of 21089401 is about 276.2833722301.

The spelling of 21089401 in words is "twenty-one million, eighty-nine thousand, four hundred one".