20390356 has 24 divisors (see below), whose sum is σ = 40876416. Its totient is φ = 8718240.

The previous prime is 20390353. The next prime is 20390399. The reversal of 20390356 is 65309302.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20390353) 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, 22545 + ... + 23431.

It is an arithmetic number, because the mean of its divisors is an integer number (1703184).

Almost surely, 2^20390356 is an apocalyptic number.

It is an amenable number.

20390356 is an abundant number, since it is smaller than the sum of its proper divisors (20486060).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20390356 is a wasteful number, since it uses less digits than its factorization.

20390356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1719 (or 1717 counting only the distinct ones).

The product of its (nonzero) digits is 4860, while the sum is 28.

The square root of 20390356 is about 4515.5681813034. The cubic root of 20390356 is about 273.1963772870.

Adding to 20390356 its reverse (65309302), we get a palindrome (85699658).

The spelling of 20390356 in words is "twenty million, three hundred ninety thousand, three hundred fifty-six".