21617793 has 8 divisors (see below), whose sum is σ = 32026400. Its totient is φ = 14411844.

The previous prime is 21617779. The next prime is 21617807. The reversal of 21617793 is 39771612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21617779) and next prime (21617807).

It is not a de Polignac number, because 21617793 - 2¹⁶ = 21552257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21617773) 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, 400303 + ... + 400356.

It is an arithmetic number, because the mean of its divisors is an integer number (4003300).

Almost surely, 2^21617793 is an apocalyptic number.

It is an amenable number.

21617793 is a deficient number, since it is larger than the sum of its proper divisors (10408607).

21617793 is an equidigital number, since it uses as much as digits as its factorization.

21617793 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 800668 (or 800662 counting only the distinct ones).

The product of its digits is 15876, while the sum is 36.

The square root of 21617793 is about 4649.4938434199. The cubic root of 21617793 is about 278.5717792050.

The spelling of 21617793 in words is "twenty-one million, six hundred seventeen thousand, seven hundred ninety-three".