21890353 has 4 divisors (see below), whose sum is σ = 22029940. Its totient is φ = 21750768.

The previous prime is 21890329. The next prime is 21890369. The reversal of 21890353 is 35309812.

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 3717184 + 18173169 = 1928^2 + 4263^2 .

It is a cyclic number.

It is not a de Polignac number, because 21890353 - 2⁹ = 21889841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21890383) 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, 69558 + ... + 69871.

It is an arithmetic number, because the mean of its divisors is an integer number (5507485).

Almost surely, 2^21890353 is an apocalyptic number.

It is an amenable number.

21890353 is a deficient number, since it is larger than the sum of its proper divisors (139587).

21890353 is a wasteful number, since it uses less digits than its factorization.

21890353 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139586.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 21890353 is about 4678.7127503193. The cubic root of 21890353 is about 279.7376496717.

The spelling of 21890353 in words is "twenty-one million, eight hundred ninety thousand, three hundred fifty-three".