21793709 has 4 divisors (see below), whose sum is σ = 24907104. Its totient is φ = 18680316.

The previous prime is 21793699. The next prime is 21793721. The reversal of 21793709 is 90739712.

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 21793709 - 2¹² = 21789613 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21793769) 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, 1556687 + ... + 1556700.

It is an arithmetic number, because the mean of its divisors is an integer number (6226776).

Almost surely, 2^21793709 is an apocalyptic number.

It is an amenable number.

21793709 is a deficient number, since it is larger than the sum of its proper divisors (3113395).

21793709 is an equidigital number, since it uses as much as digits as its factorization.

21793709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3113394.

The product of its (nonzero) digits is 23814, while the sum is 38.

The square root of 21793709 is about 4668.3732712798. The cubic root of 21793709 is about 279.3253699039.

The spelling of 21793709 in words is "twenty-one million, seven hundred ninety-three thousand, seven hundred nine".