21695423 has 2 divisors, whose sum is σ = 21695424. Its totient is φ = 21695422.

The previous prime is 21695407. The next prime is 21695449. The reversal of 21695423 is 32459612.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21695423 - 2⁴ = 21695407 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21695423.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21695483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10847711 + 10847712.

It is an arithmetic number, because the mean of its divisors is an integer number (10847712).

Almost surely, 2^21695423 is an apocalyptic number.

21695423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21695423 is an equidigital number, since it uses as much as digits as its factorization.

21695423 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 32.

The square root of 21695423 is about 4657.8345827219. The cubic root of 21695423 is about 278.9048334444.

The spelling of 21695423 in words is "twenty-one million, six hundred ninety-five thousand, four hundred twenty-three".