20390051 has 4 divisors (see below), whose sum is σ = 22243704. Its totient is φ = 18536400.

The previous prime is 20390047. The next prime is 20390077. The reversal of 20390051 is 15009302.

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

It is a cyclic number.

It is not a de Polignac number, because 20390051 - 2² = 20390047 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20390011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 926810 + ... + 926831.

It is an arithmetic number, because the mean of its divisors is an integer number (5560926).

Almost surely, 2^20390051 is an apocalyptic number.

20390051 is a deficient number, since it is larger than the sum of its proper divisors (1853653).

20390051 is a wasteful number, since it uses less digits than its factorization.

20390051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1853652.

The product of its (nonzero) digits is 270, while the sum is 20.

The square root of 20390051 is about 4515.5344091259. The cubic root of 20390051 is about 273.1950151184.

Adding to 20390051 its reverse (15009302), we get a palindrome (35399353).

The spelling of 20390051 in words is "twenty million, three hundred ninety thousand, fifty-one".