21670190 has 8 divisors (see below), whose sum is σ = 39006360. Its totient is φ = 8668072.

The previous prime is 21670183. The next prime is 21670199. The reversal of 21670190 is 9107612.

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

It is a super-2 number, since 2×21670190² = 939194269272200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21670199) 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, 1083500 + ... + 1083519.

It is an arithmetic number, because the mean of its divisors is an integer number (4875795).

Almost surely, 2^21670190 is an apocalyptic number.

21670190 is a deficient number, since it is larger than the sum of its proper divisors (17336170).

21670190 is a wasteful number, since it uses less digits than its factorization.

21670190 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2167026.

The product of its (nonzero) digits is 756, while the sum is 26.

The square root of 21670190 is about 4655.1251325824. The cubic root of 21670190 is about 278.7966641498.

Subtracting from 21670190 its reverse (9107612), we obtain a triangular number (12562578 = T₅₀₁₂).

The spelling of 21670190 in words is "twenty-one million, six hundred seventy thousand, one hundred ninety".