20404989 has 24 divisors (see below), whose sum is σ = 32572800. Its totient is φ = 12205440.

The previous prime is 20404987. The next prime is 20404991. The reversal of 20404989 is 98940402.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20404987) and next prime (20404991).

It is not a de Polignac number, because 20404989 - 2¹ = 20404987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20404987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6517 + ... + 9125.

It is an arithmetic number, because the mean of its divisors is an integer number (1357200).

Almost surely, 2^20404989 is an apocalyptic number.

It is an amenable number.

20404989 is a deficient number, since it is larger than the sum of its proper divisors (12167811).

20404989 is a wasteful number, since it uses less digits than its factorization.

20404989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2705 (or 2702 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 20404989 is about 4517.1881740747. The cubic root of 20404989 is about 273.2617141660.

The spelling of 20404989 in words is "twenty million, four hundred four thousand, nine hundred eighty-nine".