21716965 has 8 divisors (see below), whose sum is σ = 26764920. Its totient is φ = 16903872.

The previous prime is 21716963. The next prime is 21716977. The reversal of 21716965 is 56961712.

It can be written as a sum of positive squares in 4 ways, for example, as 5987809 + 15729156 = 2447^2 + 3966^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21716965 - 2¹ = 21716963 is a prime.

It is a super-2 number, since 2×21716965² = 943253137622450, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21716963) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58510 + ... + 58879.

It is an arithmetic number, because the mean of its divisors is an integer number (3345615).

Almost surely, 2^21716965 is an apocalyptic number.

It is an amenable number.

21716965 is a deficient number, since it is larger than the sum of its proper divisors (5047955).

21716965 is a wasteful number, since it uses less digits than its factorization.

21716965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117431.

The product of its digits is 22680, while the sum is 37.

The square root of 21716965 is about 4660.1464569260. The cubic root of 21716965 is about 278.9971137448.

The spelling of 21716965 in words is "twenty-one million, seven hundred sixteen thousand, nine hundred sixty-five".