20490913 has 4 divisors (see below), whose sum is σ = 20877588. Its totient is φ = 20104240.

The previous prime is 20490839. The next prime is 20490917. The reversal of 20490913 is 31909402.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 9941409 + 10549504 = 3153^2 + 3248^2 .

It is a cyclic number.

It is not a de Polignac number, because 20490913 - 2²¹ = 18393761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20490917) 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, 193258 + ... + 193363.

It is an arithmetic number, because the mean of its divisors is an integer number (5219397).

Almost surely, 2^20490913 is an apocalyptic number.

It is an amenable number.

20490913 is a deficient number, since it is larger than the sum of its proper divisors (386675).

20490913 is an equidigital number, since it uses as much as digits as its factorization.

20490913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 386674.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 20490913 is about 4526.6889665626. The cubic root of 20490913 is about 273.6447391087.

The spelling of 20490913 in words is "twenty million, four hundred ninety thousand, nine hundred thirteen".