21716693 has 2 divisors, whose sum is σ = 21716694. Its totient is φ = 21716692.

The previous prime is 21716683. The next prime is 21716713. The reversal of 21716693 is 39661712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21464689 + 252004 = 4633^2 + 502^2 .

It is a cyclic number.

It is not a de Polignac number, because 21716693 - 2⁸ = 21716437 is a prime.

It is a super-2 number, since 2×21716693² = 943229509712498, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21716603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10858346 + 10858347.

It is an arithmetic number, because the mean of its divisors is an integer number (10858347).

Almost surely, 2^21716693 is an apocalyptic number.

It is an amenable number.

21716693 is a deficient number, since it is larger than the sum of its proper divisors (1).

21716693 is an equidigital number, since it uses as much as digits as its factorization.

21716693 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13608, while the sum is 35.

The square root of 21716693 is about 4660.1172732025. The cubic root of 21716693 is about 278.9959489483.

The spelling of 21716693 in words is "twenty-one million, seven hundred sixteen thousand, six hundred ninety-three".