20495989 has 4 divisors (see below), whose sum is σ = 20509056. Its totient is φ = 20482924.

The previous prime is 20495987. The next prime is 20496017. The reversal of 20495989 is 98959402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20495989 - 2¹ = 20495987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20495987) 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, 3799 + ... + 7444.

It is an arithmetic number, because the mean of its divisors is an integer number (5127264).

Almost surely, 2^20495989 is an apocalyptic number.

It is an amenable number.

20495989 is a deficient number, since it is larger than the sum of its proper divisors (13067).

20495989 is a wasteful number, since it uses less digits than its factorization.

20495989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13066.

The product of its (nonzero) digits is 233280, while the sum is 46.

The square root of 20495989 is about 4527.2496065492. The cubic root of 20495989 is about 273.6673329615.

The spelling of 20495989 in words is "twenty million, four hundred ninety-five thousand, nine hundred eighty-nine".