20491604 has 18 divisors (see below), whose sum is σ = 41715450. Its totient is φ = 8782032.

The previous prime is 20491591. The next prime is 20491609. The reversal of 20491604 is 40619402.

It can be written as a sum of positive squares in only one way, i.e., 16483600 + 4008004 = 4060^2 + 2002^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20491609) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 52079 + ... + 52470.

It is an arithmetic number, because the mean of its divisors is an integer number (2317525).

Almost surely, 2^20491604 is an apocalyptic number.

It is an amenable number.

20491604 is an abundant number, since it is smaller than the sum of its proper divisors (21223846).

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

20491604 is a wasteful number, since it uses less digits than its factorization.

20491604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104567 (or 104558 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 20491604 is about 4526.7652910218. The cubic root of 20491604 is about 273.6478150476.

The spelling of 20491604 in words is "twenty million, four hundred ninety-one thousand, six hundred four".