21292753 has 4 divisors (see below), whose sum is σ = 21979648. Its totient is φ = 20605860.

The previous prime is 21292751. The next prime is 21292759. The reversal of 21292753 is 35729212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21292753 - 2¹ = 21292751 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 686863 = 21292753 / (2 + 1 + 2 + 9 + 2 + 7 + 5 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21292751) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 343401 + ... + 343462.

It is an arithmetic number, because the mean of its divisors is an integer number (5494912).

Almost surely, 2^21292753 is an apocalyptic number.

It is an amenable number.

21292753 is a deficient number, since it is larger than the sum of its proper divisors (686895).

21292753 is an equidigital number, since it uses as much as digits as its factorization.

21292753 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 686894.

The product of its digits is 7560, while the sum is 31.

The square root of 21292753 is about 4614.4071125119. The cubic root of 21292753 is about 277.1685429205.

The spelling of 21292753 in words is "twenty-one million, two hundred ninety-two thousand, seven hundred fifty-three".