20509844 has 12 divisors (see below), whose sum is σ = 37130100. Its totient is φ = 9901248.

The previous prime is 20509843. The next prime is 20509891. The reversal of 20509844 is 44890502.

It can be written as a sum of positive squares in 2 ways, for example, as 12602500 + 7907344 = 3550^2 + 2812^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20509844.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20509843) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 88289 + ... + 88520.

It is an arithmetic number, because the mean of its divisors is an integer number (3094175).

Almost surely, 2^20509844 is an apocalyptic number.

It is an amenable number.

20509844 is a deficient number, since it is larger than the sum of its proper divisors (16620256).

20509844 is a wasteful number, since it uses less digits than its factorization.

20509844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176842 (or 176840 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 20509844 is about 4528.7795265391. The cubic root of 20509844 is about 273.7289841598.

The spelling of 20509844 in words is "twenty million, five hundred nine thousand, eight hundred forty-four".