20406824 has 8 divisors (see below), whose sum is σ = 38262810. Its totient is φ = 10203408.

The previous prime is 20406823. The next prime is 20406829. The reversal of 20406824 is 42860402.

It can be written as a sum of positive squares in only one way, i.e., 16728100 + 3678724 = 4090^2 + 1918^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 20406793 and 20406802.

It is not an unprimeable number, because it can be changed into a prime (20406823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1275419 + ... + 1275434.

Almost surely, 2^20406824 is an apocalyptic number.

It is an amenable number.

20406824 is a deficient number, since it is larger than the sum of its proper divisors (17855986).

20406824 is a wasteful number, since it uses less digits than its factorization.

20406824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2550859 (or 2550855 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 26.

The square root of 20406824 is about 4517.3912825878. The cubic root of 20406824 is about 273.2699053036.

The spelling of 20406824 in words is "twenty million, four hundred six thousand, eight hundred twenty-four".