20128247 has 4 divisors (see below), whose sum is σ = 20370840. Its totient is φ = 19885656.

The previous prime is 20128223. The next prime is 20128279. The reversal of 20128247 is 74282102.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20128247 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 (20128447) 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, 121172 + ... + 121337.

It is an arithmetic number, because the mean of its divisors is an integer number (5092710).

Almost surely, 2^20128247 is an apocalyptic number.

20128247 is a deficient number, since it is larger than the sum of its proper divisors (242593).

20128247 is an equidigital number, since it uses as much as digits as its factorization.

20128247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242592.

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 20128247 is about 4486.4514931068. The cubic root of 20128247 is about 272.0207191181.

The spelling of 20128247 in words is "twenty million, one hundred twenty-eight thousand, two hundred forty-seven".