20747851 has 4 divisors (see below), whose sum is σ = 20772232. Its totient is φ = 20723472.

The previous prime is 20747827. The next prime is 20747873. The reversal of 20747851 is 15874702.

It is a happy number.

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 20747851 - 2⁵ = 20747819 is a prime.

It is a super-2 number, since 2×20747851² = 860946642236402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20727851) 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, 10866 + ... + 12631.

It is an arithmetic number, because the mean of its divisors is an integer number (5193058).

Almost surely, 2^20747851 is an apocalyptic number.

20747851 is a deficient number, since it is larger than the sum of its proper divisors (24381).

20747851 is an equidigital number, since it uses as much as digits as its factorization.

20747851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24380.

The product of its (nonzero) digits is 15680, while the sum is 34.

The square root of 20747851 is about 4554.9809000697. The cubic root of 20747851 is about 274.7837462410.

The spelling of 20747851 in words is "twenty million, seven hundred forty-seven thousand, eight hundred fifty-one".