20748731 has 4 divisors (see below), whose sum is σ = 20763600. Its totient is φ = 20733864.

The previous prime is 20748727. The next prime is 20748751. The reversal of 20748731 is 13784702.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13784702 = 2 ⋅6892351.

It is a cyclic number.

It is not a de Polignac number, because 20748731 - 2² = 20748727 is a prime.

It is a super-2 number, since 2×20748731² = 861019676220722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20748701) 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, 5096 + ... + 8213.

It is an arithmetic number, because the mean of its divisors is an integer number (5190900).

Almost surely, 2^20748731 is an apocalyptic number.

20748731 is a deficient number, since it is larger than the sum of its proper divisors (14869).

20748731 is a wasteful number, since it uses less digits than its factorization.

20748731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14868.

The product of its (nonzero) digits is 9408, while the sum is 32.

The square root of 20748731 is about 4555.0774965965. The cubic root of 20748731 is about 274.7876310815.

The spelling of 20748731 in words is "twenty million, seven hundred forty-eight thousand, seven hundred thirty-one".