21793749 has 4 divisors (see below), whose sum is σ = 29058336. Its totient is φ = 14529164.

The previous prime is 21793747. The next prime is 21793757. The reversal of 21793749 is 94739712.

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 21793749 - 2¹ = 21793747 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21793749.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21793747) 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, 3632289 + ... + 3632294.

It is an arithmetic number, because the mean of its divisors is an integer number (7264584).

Almost surely, 2^21793749 is an apocalyptic number.

It is an amenable number.

21793749 is a deficient number, since it is larger than the sum of its proper divisors (7264587).

21793749 is an equidigital number, since it uses as much as digits as its factorization.

21793749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7264586.

The product of its digits is 95256, while the sum is 42.

The square root of 21793749 is about 4668.3775554254. The cubic root of 21793749 is about 279.3255407943.

The spelling of 21793749 in words is "twenty-one million, seven hundred ninety-three thousand, seven hundred forty-nine".