20390623 has 8 divisors (see below), whose sum is σ = 22277376. Its totient is φ = 18509400.

The previous prime is 20390609. The next prime is 20390639. The reversal of 20390623 is 32609302.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20390623 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20390323) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12090 + ... + 13672.

It is an arithmetic number, because the mean of its divisors is an integer number (2784672).

Almost surely, 2^20390623 is an apocalyptic number.

20390623 is a deficient number, since it is larger than the sum of its proper divisors (1886753).

20390623 is a wasteful number, since it uses less digits than its factorization.

20390623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2765.

The product of its (nonzero) digits is 1944, while the sum is 25.

The square root of 20390623 is about 4515.5977455925. The cubic root of 20390623 is about 273.1975697317.

Adding to 20390623 its reverse (32609302), we get a palindrome (52999925).

The spelling of 20390623 in words is "twenty million, three hundred ninety thousand, six hundred twenty-three".