20715749 has 4 divisors (see below), whose sum is σ = 20741280. Its totient is φ = 20690220.

The previous prime is 20715731. The next prime is 20715763. The reversal of 20715749 is 94751702.

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 20715749 - 2⁸ = 20715493 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 (20715349) 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, 11507 + ... + 13184.

It is an arithmetic number, because the mean of its divisors is an integer number (5185320).

Almost surely, 2^20715749 is an apocalyptic number.

It is an amenable number.

20715749 is a deficient number, since it is larger than the sum of its proper divisors (25531).

20715749 is an equidigital number, since it uses as much as digits as its factorization.

20715749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25530.

The product of its (nonzero) digits is 17640, while the sum is 35.

The square root of 20715749 is about 4551.4557012015. The cubic root of 20715749 is about 274.6419538660.

The spelling of 20715749 in words is "twenty million, seven hundred fifteen thousand, seven hundred forty-nine".