21694793 has 2 divisors, whose sum is σ = 21694794. Its totient is φ = 21694792.

The previous prime is 21694763. The next prime is 21694817. The reversal of 21694793 is 39749612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19465744 + 2229049 = 4412^2 + 1493^2 .

It is a cyclic number.

It is not a de Polignac number, because 21694793 - 2⁸ = 21694537 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21694793.

It is not a weakly prime, because it can be changed into another prime (21694723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10847396 + 10847397.

It is an arithmetic number, because the mean of its divisors is an integer number (10847397).

Almost surely, 2^21694793 is an apocalyptic number.

It is an amenable number.

21694793 is a deficient number, since it is larger than the sum of its proper divisors (1).

21694793 is an equidigital number, since it uses as much as digits as its factorization.

21694793 is an evil number, because the sum of its binary digits is even.

The product of its digits is 81648, while the sum is 41.

The square root of 21694793 is about 4657.7669542389. The cubic root of 21694793 is about 278.9021337698.

The spelling of 21694793 in words is "twenty-one million, six hundred ninety-four thousand, seven hundred ninety-three".