20390953 has 4 divisors (see below), whose sum is σ = 22244688. Its totient is φ = 18537220.

The previous prime is 20390947. The next prime is 20391037. The reversal of 20390953 is 35909302.

It is the 1844-th star number.

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 20390953 - 2¹⁷ = 20259881 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20390353) 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, 926851 + ... + 926872.

It is an arithmetic number, because the mean of its divisors is an integer number (5561172).

Almost surely, 2^20390953 is an apocalyptic number.

It is an amenable number.

20390953 is a deficient number, since it is larger than the sum of its proper divisors (1853735).

20390953 is a wasteful number, since it uses less digits than its factorization.

20390953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1853734.

The product of its (nonzero) digits is 7290, while the sum is 31.

The square root of 20390953 is about 4515.6342854576. The cubic root of 20390953 is about 273.1990435254.

The spelling of 20390953 in words is "twenty million, three hundred ninety thousand, nine hundred fifty-three".