20490813 has 40 divisors (see below), whose sum is σ = 35544960. Its totient is φ = 11521440.

The previous prime is 20490803. The next prime is 20490823. The reversal of 20490813 is 31809402.

It is an interprime number because it is at equal distance from previous prime (20490803) and next prime (20490823).

It is not a de Polignac number, because 20490813 - 2⁶ = 20490749 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20490803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 40003 + ... + 40511.

It is an arithmetic number, because the mean of its divisors is an integer number (888624).

Almost surely, 2^20490813 is an apocalyptic number.

It is an amenable number.

20490813 is a deficient number, since it is larger than the sum of its proper divisors (15054147).

20490813 is an equidigital number, since it uses as much as digits as its factorization.

20490813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 599 (or 590 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 20490813 is about 4526.6779209482. The cubic root of 20490813 is about 273.6442939598.

The spelling of 20490813 in words is "twenty million, four hundred ninety thousand, eight hundred thirteen".