21917190 has 16 divisors (see below), whose sum is σ = 52601328. Its totient is φ = 5844576.

The previous prime is 21917177. The next prime is 21917201. The reversal of 21917190 is 9171912.

It is a super-2 number, since 2×21917190² = 960726434992200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 730573 = 21917190 / (2 + 1 + 9 + 1 + 7 + 1 + 9 + 0).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 365257 + ... + 365316.

It is an arithmetic number, because the mean of its divisors is an integer number (3287583).

Almost surely, 2^21917190 is an apocalyptic number.

21917190 is an abundant number, since it is smaller than the sum of its proper divisors (30684138).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21917190 is a wasteful number, since it uses less digits than its factorization.

21917190 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 730583.

The product of its (nonzero) digits is 1134, while the sum is 30.

The square root of 21917190 is about 4681.5798615425. The cubic root of 21917190 is about 279.8519200000.

The spelling of 21917190 in words is "twenty-one million, nine hundred seventeen thousand, one hundred ninety".