20749717 has 4 divisors (see below), whose sum is σ = 20772576. Its totient is φ = 20726860.

The previous prime is 20749697. The next prime is 20749721. The reversal of 20749717 is 71794702.

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 a de Polignac number, because none of the positive numbers 2^k-20749717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20749747) 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, 10009 + ... + 11902.

It is an arithmetic number, because the mean of its divisors is an integer number (5193144).

Almost surely, 2^20749717 is an apocalyptic number.

It is an amenable number.

20749717 is a deficient number, since it is larger than the sum of its proper divisors (22859).

20749717 is an equidigital number, since it uses as much as digits as its factorization.

20749717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22858.

The product of its (nonzero) digits is 24696, while the sum is 37.

The square root of 20749717 is about 4555.1857261807. The cubic root of 20749717 is about 274.7919837383.

The spelling of 20749717 in words is "twenty million, seven hundred forty-nine thousand, seven hundred seventeen".