21713693 has 2 divisors, whose sum is σ = 21713694. Its totient is φ = 21713692.

The previous prime is 21713683. The next prime is 21713707. The reversal of 21713693 is 39631712.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12581209 + 9132484 = 3547^2 + 3022^2 .

It is a cyclic number.

It is not a de Polignac number, because 21713693 - 2⁴ = 21713677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21713603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10856846 + 10856847.

It is an arithmetic number, because the mean of its divisors is an integer number (10856847).

Almost surely, 2^21713693 is an apocalyptic number.

It is an amenable number.

21713693 is a deficient number, since it is larger than the sum of its proper divisors (1).

21713693 is an equidigital number, since it uses as much as digits as its factorization.

21713693 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6804, while the sum is 32.

The square root of 21713693 is about 4659.7953817738. The cubic root of 21713693 is about 278.9831012833.

The spelling of 21713693 in words is "twenty-one million, seven hundred thirteen thousand, six hundred ninety-three".