20389861 has 4 divisors (see below), whose sum is σ = 20418412. Its totient is φ = 20361312.

The previous prime is 20389843. The next prime is 20389879. The reversal of 20389861 is 16898302.

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

It is an interprime number because it is at equal distance from previous prime (20389843) and next prime (20389879).

It can be written as a sum of positive squares in 2 ways, for example, as 16760836 + 3629025 = 4094^2 + 1905^2 .

It is a cyclic number.

It is not a de Polignac number, because 20389861 - 2⁵ = 20389829 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 20389861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20389801) 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, 13176 + ... + 14641.

It is an arithmetic number, because the mean of its divisors is an integer number (5104603).

Almost surely, 2^20389861 is an apocalyptic number.

It is an amenable number.

20389861 is a deficient number, since it is larger than the sum of its proper divisors (28551).

20389861 is an equidigital number, since it uses as much as digits as its factorization.

20389861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28550.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 20389861 is about 4515.5133705925. The cubic root of 20389861 is about 273.1941665475.

The spelling of 20389861 in words is "twenty million, three hundred eighty-nine thousand, eight hundred sixty-one".