20306689 has 4 divisors (see below), whose sum is σ = 21868756. Its totient is φ = 18744624.

The previous prime is 20306681. The next prime is 20306701. The reversal of 20306689 is 98660302.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2666689 + 17640000 = 1633^2 + 4200^2 .

It is a cyclic number.

It is not a de Polignac number, because 20306689 - 2³ = 20306681 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20306681) 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, 781014 + ... + 781039.

It is an arithmetic number, because the mean of its divisors is an integer number (5467189).

Almost surely, 2^20306689 is an apocalyptic number.

It is an amenable number.

20306689 is a deficient number, since it is larger than the sum of its proper divisors (1562067).

20306689 is a wasteful number, since it uses less digits than its factorization.

20306689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1562066.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 20306689 is about 4506.2943756484. The cubic root of 20306689 is about 272.8221994774.

The spelling of 20306689 in words is "twenty million, three hundred six thousand, six hundred eighty-nine".