21890695 has 4 divisors (see below), whose sum is σ = 26268840. Its totient is φ = 17512552.

The previous prime is 21890689. The next prime is 21890719. The reversal of 21890695 is 59609812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21890695 - 2¹⁷ = 21759623 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

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, 2189065 + ... + 2189074.

It is an arithmetic number, because the mean of its divisors is an integer number (6567210).

Almost surely, 2^21890695 is an apocalyptic number.

21890695 is a deficient number, since it is larger than the sum of its proper divisors (4378145).

21890695 is an equidigital number, since it uses as much as digits as its factorization.

21890695 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4378144.

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 21890695 is about 4678.7492986908. The cubic root of 21890695 is about 279.7391064745.

The spelling of 21890695 in words is "twenty-one million, eight hundred ninety thousand, six hundred ninety-five".