20747839 has 4 divisors (see below), whose sum is σ = 23711824. Its totient is φ = 17783856.

The previous prime is 20747827. The next prime is 20747873. The reversal of 20747839 is 93874702.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20747839 - 2¹⁹ = 20223551 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 (20747809) 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, 1481982 + ... + 1481995.

It is an arithmetic number, because the mean of its divisors is an integer number (5927956).

Almost surely, 2^20747839 is an apocalyptic number.

20747839 is a deficient number, since it is larger than the sum of its proper divisors (2963985).

20747839 is an equidigital number, since it uses as much as digits as its factorization.

20747839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2963984.

The product of its (nonzero) digits is 84672, while the sum is 40.

The square root of 20747839 is about 4554.9795828302. The cubic root of 20747839 is about 274.7836932651.

The spelling of 20747839 in words is "twenty million, seven hundred forty-seven thousand, eight hundred thirty-nine".