21399190 has 8 divisors (see below), whose sum is σ = 38518560. Its totient is φ = 8559672.

The previous prime is 21399181. The next prime is 21399193. The reversal of 21399190 is 9199312.

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

It is a super-2 number, since 2×21399190² = 915850665312200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21399193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1069950 + ... + 1069969.

It is an arithmetic number, because the mean of its divisors is an integer number (4814820).

Almost surely, 2^21399190 is an apocalyptic number.

21399190 is a deficient number, since it is larger than the sum of its proper divisors (17119370).

21399190 is a wasteful number, since it uses less digits than its factorization.

21399190 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2139926.

The product of its (nonzero) digits is 4374, while the sum is 34.

The square root of 21399190 is about 4625.9258532752. The cubic root of 21399190 is about 277.6296069627.

The spelling of 21399190 in words is "twenty-one million, three hundred ninety-nine thousand, one hundred ninety".