21694810 has 16 divisors (see below), whose sum is σ = 39108096. Its totient is φ = 8665168.

The previous prime is 21694793. The next prime is 21694817. The reversal of 21694810 is 1849612.

It is a happy number.

It is a super-2 number, since 2×21694810² = 941329561872200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21694817) 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 7 ways as a sum of consecutive naturals, for example, 8727 + ... + 10933.

It is an arithmetic number, because the mean of its divisors is an integer number (2444256).

Almost surely, 2^21694810 is an apocalyptic number.

21694810 is a deficient number, since it is larger than the sum of its proper divisors (17413286).

21694810 is a wasteful number, since it uses less digits than its factorization.

21694810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3197.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 21694810 is about 4657.7687791474. The cubic root of 21694810 is about 278.9022066188.

The spelling of 21694810 in words is "twenty-one million, six hundred ninety-four thousand, eight hundred ten".