20553689 has 4 divisors (see below), whose sum is σ = 22134756. Its totient is φ = 18972624.

The previous prime is 20553647. The next prime is 20553691. The reversal of 20553689 is 98635502.

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 6416089 + 14137600 = 2533^2 + 3760^2 .

It is a cyclic number.

It is not a de Polignac number, because 20553689 - 2⁸ = 20553433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20553619) 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, 790514 + ... + 790539.

It is an arithmetic number, because the mean of its divisors is an integer number (5533689).

Almost surely, 2^20553689 is an apocalyptic number.

It is an amenable number.

20553689 is a deficient number, since it is larger than the sum of its proper divisors (1581067).

20553689 is a wasteful number, since it uses less digits than its factorization.

20553689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1581066.

The product of its (nonzero) digits is 64800, while the sum is 38.

The square root of 20553689 is about 4533.6176503980. The cubic root of 20553689 is about 273.9239004037.

The spelling of 20553689 in words is "twenty million, five hundred fifty-three thousand, six hundred eighty-nine".