21390194 has 16 divisors (see below), whose sum is σ = 36739008. Its totient is φ = 9149712.

The previous prime is 21390163. The next prime is 21390247. The reversal of 21390194 is 49109312.

It is a happy number.

It is a Curzon 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, 8444 + ... + 10680.

It is an arithmetic number, because the mean of its divisors is an integer number (2296188).

Almost surely, 2^21390194 is an apocalyptic number.

21390194 is a deficient number, since it is larger than the sum of its proper divisors (15348814).

21390194 is a wasteful number, since it uses less digits than its factorization.

21390194 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2929.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 21390194 is about 4624.9534051707. The cubic root of 21390194 is about 277.5906972967.

The spelling of 21390194 in words is "twenty-one million, three hundred ninety thousand, one hundred ninety-four".