20740689 has 6 divisors (see below), whose sum is σ = 29958786. Its totient is φ = 13827120.

The previous prime is 20740679. The next prime is 20740691. The reversal of 20740689 is 98604702.

It can be written as a sum of positive squares in only one way, i.e., 17918289 + 2822400 = 4233^2 + 1680^2 .

It is not a de Polignac number, because 20740689 - 2⁴ = 20740673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20740679) 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 5 ways as a sum of consecutive naturals, for example, 1152252 + ... + 1152269.

It is an arithmetic number, because the mean of its divisors is an integer number (4993131).

Almost surely, 2^20740689 is an apocalyptic number.

It is an amenable number.

20740689 is a deficient number, since it is larger than the sum of its proper divisors (9218097).

20740689 is a wasteful number, since it uses less digits than its factorization.

20740689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2304527 (or 2304524 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 20740689 is about 4554.1946598713. The cubic root of 20740689 is about 274.7521248507.

The spelling of 20740689 in words is "twenty million, seven hundred forty thousand, six hundred eighty-nine".