21696965 has 8 divisors (see below), whose sum is σ = 26095608. Its totient is φ = 17318080.

The previous prime is 21696953. The next prime is 21696967. The reversal of 21696965 is 56969612.

It is a Cunningham number, because it is equal to 4658²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 6959044 + 14737921 = 2638^2 + 3839^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21696965 - 2¹⁰ = 21695941 is a prime.

It is a super-2 number, since 2×21696965² = 941516580422450, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21696967) 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, 2402 + ... + 7011.

It is an arithmetic number, because the mean of its divisors is an integer number (3261951).

Almost surely, 2^21696965 is an apocalyptic number.

It is an amenable number.

21696965 is a deficient number, since it is larger than the sum of its proper divisors (4398643).

21696965 is an equidigital number, since it uses as much as digits as its factorization.

21696965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9879.

The product of its digits is 174960, while the sum is 44.

The square root of 21696965 is about 4658.0001073422. Note that the first 3 decimals coincide. The cubic root of 21696965 is about 278.9114409988.

The spelling of 21696965 in words is "twenty-one million, six hundred ninety-six thousand, nine hundred sixty-five".