20490138 has 32 divisors (see below), whose sum is σ = 45681600. Its totient is φ = 6807888.

The previous prime is 20490133. The next prime is 20490149. The reversal of 20490138 is 83109402.

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 (20490133) 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 15 ways as a sum of consecutive naturals, for example, 32793 + ... + 33411.

It is an arithmetic number, because the mean of its divisors is an integer number (1427550).

Almost surely, 2^20490138 is an apocalyptic number.

20490138 is an abundant number, since it is smaller than the sum of its proper divisors (25191462).

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

20490138 is a wasteful number, since it uses less digits than its factorization.

20490138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1243 (or 1237 counting only the distinct ones).

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

The square root of 20490138 is about 4526.6033623458. The cubic root of 20490138 is about 273.6412891673.

The spelling of 20490138 in words is "twenty million, four hundred ninety thousand, one hundred thirty-eight".