21890197 has 8 divisors (see below), whose sum is σ = 25084800. Its totient is φ = 18712464.

The previous prime is 21890159. The next prime is 21890201. The reversal of 21890197 is 79109812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21890197 - 2²³ = 13501589 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 (21890107) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1297 + ... + 6742.

It is an arithmetic number, because the mean of its divisors is an integer number (3135600).

Almost surely, 2^21890197 is an apocalyptic number.

It is an amenable number.

21890197 is a deficient number, since it is larger than the sum of its proper divisors (3194603).

21890197 is an equidigital number, since it uses as much as digits as its factorization.

21890197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8435.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 21890197 is about 4678.6960790374. The cubic root of 21890197 is about 279.7369851602.

The spelling of 21890197 in words is "twenty-one million, eight hundred ninety thousand, one hundred ninety-seven".