21316965 has 16 divisors (see below), whose sum is σ = 34540800. Its totient is φ = 11224512.

The previous prime is 21316903. The next prime is 21316987. The reversal of 21316965 is 56961312.

It is a happy number.

It is not a de Polignac number, because 21316965 - 2²¹ = 19219813 is a prime.

It is a super-2 number, since 2×21316965² = 908825993622450, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 7810 + ... + 10179.

It is an arithmetic number, because the mean of its divisors is an integer number (2158800).

Almost surely, 2^21316965 is an apocalyptic number.

It is an amenable number.

21316965 is a deficient number, since it is larger than the sum of its proper divisors (13223835).

21316965 is a wasteful number, since it uses less digits than its factorization.

21316965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18076.

The product of its digits is 9720, while the sum is 33.

The square root of 21316965 is about 4617.0298894419. The cubic root of 21316965 is about 277.2735592883.

The spelling of 21316965 in words is "twenty-one million, three hundred sixteen thousand, nine hundred sixty-five".