21320465 has 8 divisors (see below), whose sum is σ = 27089640. Its totient is φ = 16052992.

The previous prime is 21320447. The next prime is 21320479. The reversal of 21320465 is 56402312.

It can be written as a sum of positive squares in 4 ways, for example, as 5071504 + 16248961 = 2252^2 + 4031^2 .

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 21320465 - 2⁶ = 21320401 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21320465.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 125330 + ... + 125499.

It is an arithmetic number, because the mean of its divisors is an integer number (3386205).

Almost surely, 2^21320465 is an apocalyptic number.

It is an amenable number.

21320465 is a deficient number, since it is larger than the sum of its proper divisors (5769175).

21320465 is a wasteful number, since it uses less digits than its factorization.

21320465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250851.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21320465 is about 4617.4089054360. The cubic root of 21320465 is about 277.2887334990.

Adding to 21320465 its reverse (56402312), we get a palindrome (77722777).

The spelling of 21320465 in words is "twenty-one million, three hundred twenty thousand, four hundred sixty-five".