20398789 has 4 divisors (see below), whose sum is σ = 20443500. Its totient is φ = 20354080.

The previous prime is 20398787. The next prime is 20398817. The reversal of 20398789 is 98789302.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98789302 = 2 ⋅49394651.

It can be written as a sum of positive squares in 2 ways, for example, as 2505889 + 17892900 = 1583^2 + 4230^2 .

It is a cyclic number.

It is not a de Polignac number, because 20398789 - 2¹ = 20398787 is a prime.

It is a super-2 number, since 2×20398789² = 832221185333042, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20398787) 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, 21664 + ... + 22585.

It is an arithmetic number, because the mean of its divisors is an integer number (5110875).

Almost surely, 2^20398789 is an apocalyptic number.

It is an amenable number.

20398789 is a deficient number, since it is larger than the sum of its proper divisors (44711).

20398789 is an equidigital number, since it uses as much as digits as its factorization.

20398789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44710.

The product of its (nonzero) digits is 217728, while the sum is 46.

The square root of 20398789 is about 4516.5018543116. The cubic root of 20398789 is about 273.2340347547.

The spelling of 20398789 in words is "twenty million, three hundred ninety-eight thousand, seven hundred eighty-nine".