20438649 has 80 divisors (see below), whose sum is σ = 39726720. Its totient is φ = 10160640.

The previous prime is 20438633. The next prime is 20438659. The reversal of 20438649 is 94683402.

It is a happy number.

20438649 is a `hidden beast` number, since 2 + 0 + 4 + 3 + 8 + 649 = 666.

It is not a de Polignac number, because 20438649 - 2⁴ = 20438633 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20438659) 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 79 ways as a sum of consecutive naturals, for example, 180817 + ... + 180929.

It is an arithmetic number, because the mean of its divisors is an integer number (496584).

Almost surely, 2^20438649 is an apocalyptic number.

20438649 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20438649 is a deficient number, since it is larger than the sum of its proper divisors (19288071).

20438649 is a wasteful number, since it uses less digits than its factorization.

20438649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172 (or 163 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 20438649 is about 4520.9124079106. The cubic root of 20438649 is about 273.4118888165.

The spelling of 20438649 in words is "twenty million, four hundred thirty-eight thousand, six hundred forty-nine".