21352693 has 4 divisors (see below), whose sum is σ = 21755628. Its totient is φ = 20949760.

The previous prime is 21352691. The next prime is 21352703. The reversal of 21352693 is 39625312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7387524 + 13965169 = 2718^2 + 3737^2 .

It is a cyclic number.

It is not a de Polignac number, because 21352693 - 2¹ = 21352691 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21352691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 201388 + ... + 201493.

It is an arithmetic number, because the mean of its divisors is an integer number (5438907).

Almost surely, 2^21352693 is an apocalyptic number.

It is an amenable number.

21352693 is a deficient number, since it is larger than the sum of its proper divisors (402935).

21352693 is an equidigital number, since it uses as much as digits as its factorization.

21352693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402934.

The product of its digits is 9720, while the sum is 31.

The square root of 21352693 is about 4620.8974236613. The cubic root of 21352693 is about 277.4283796449.

The spelling of 21352693 in words is "twenty-one million, three hundred fifty-two thousand, six hundred ninety-three".