20198747 has 4 divisors (see below), whose sum is σ = 20529936. Its totient is φ = 19867560.

The previous prime is 20198743. The next prime is 20198753. The reversal of 20198747 is 74789102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74789102 = 2 ⋅37394551.

It is a cyclic number.

It is not a de Polignac number, because 20198747 - 2² = 20198743 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20198747.

It is not an unprimeable number, because it can be changed into a prime (20198741) 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, 165503 + ... + 165624.

It is an arithmetic number, because the mean of its divisors is an integer number (5132484).

Almost surely, 2^20198747 is an apocalyptic number.

20198747 is a deficient number, since it is larger than the sum of its proper divisors (331189).

20198747 is an equidigital number, since it uses as much as digits as its factorization.

20198747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331188.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 20198747 is about 4494.3016142667. The cubic root of 20198747 is about 272.3379369102.

The spelling of 20198747 in words is "twenty million, one hundred ninety-eight thousand, seven hundred forty-seven".