21352665 has 8 divisors (see below), whose sum is σ = 34164288. Its totient is φ = 11388080.

The previous prime is 21352651. The next prime is 21352687. The reversal of 21352665 is 56625312.

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

It is not a de Polignac number, because 21352665 - 2⁴ = 21352649 is a prime.

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, 711741 + ... + 711770.

It is an arithmetic number, because the mean of its divisors is an integer number (4270536).

Almost surely, 2^21352665 is an apocalyptic number.

It is an amenable number.

21352665 is a deficient number, since it is larger than the sum of its proper divisors (12811623).

21352665 is a wasteful number, since it uses less digits than its factorization.

21352665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1423519.

The product of its digits is 10800, while the sum is 30.

The square root of 21352665 is about 4620.8943939458. The cubic root of 21352665 is about 277.4282583799.

Adding to 21352665 its reverse (56625312), we get a palindrome (77977977).

The spelling of 21352665 in words is "twenty-one million, three hundred fifty-two thousand, six hundred sixty-five".