21373889 has 4 divisors (see below), whose sum is σ = 21666756. Its totient is φ = 21081024.

The previous prime is 21373883. The next prime is 21373897. The reversal of 21373889 is 98837312.

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 4068289 + 17305600 = 2017^2 + 4160^2 .

It is a cyclic number.

It is not a de Polignac number, because 21373889 - 2²⁴ = 4596673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21373883) 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, 146324 + ... + 146469.

It is an arithmetic number, because the mean of its divisors is an integer number (5416689).

Almost surely, 2^21373889 is an apocalyptic number.

It is an amenable number.

21373889 is a deficient number, since it is larger than the sum of its proper divisors (292867).

21373889 is an equidigital number, since it uses as much as digits as its factorization.

21373889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 292866.

The product of its digits is 72576, while the sum is 41.

The square root of 21373889 is about 4623.1903486662. The cubic root of 21373889 is about 277.5201467937.

The spelling of 21373889 in words is "twenty-one million, three hundred seventy-three thousand, eight hundred eighty-nine".