21380965 has 8 divisors (see below), whose sum is σ = 25735320. Its totient is φ = 17052672.

The previous prime is 21380959. The next prime is 21380969. The reversal of 21380965 is 56908312.

It can be written as a sum of positive squares in 4 ways, for example, as 8836 + 21372129 = 94^2 + 4623^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21380965 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21380965.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21380969) 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, 4660 + ... + 8029.

It is an arithmetic number, because the mean of its divisors is an integer number (3216915).

Almost surely, 2^21380965 is an apocalyptic number.

It is an amenable number.

21380965 is a deficient number, since it is larger than the sum of its proper divisors (4354355).

21380965 is a wasteful number, since it uses less digits than its factorization.

21380965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13031.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 21380965 is about 4623.9555577449. The cubic root of 21380965 is about 277.5507685162.

The spelling of 21380965 in words is "twenty-one million, three hundred eighty thousand, nine hundred sixty-five".