20455840 has 24 divisors (see below), whose sum is σ = 48327300. Its totient is φ = 8182272.

The previous prime is 20455829. The next prime is 20455847. The reversal of 20455840 is 4855402.

It can be written as a sum of positive squares in 2 ways, for example, as 19044496 + 1411344 = 4364^2 + 1188^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20455799 and 20455808.

It is not an unprimeable number, because it can be changed into a prime (20455847) 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, 63765 + ... + 64084.

Almost surely, 2^20455840 is an apocalyptic number.

20455840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20455840 is an abundant number, since it is smaller than the sum of its proper divisors (27871460).

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

20455840 is a wasteful number, since it uses less digits than its factorization.

20455840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127864 (or 127856 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 28.

The square root of 20455840 is about 4522.8132837870. The cubic root of 20455840 is about 273.4885231479.

The spelling of 20455840 in words is "twenty million, four hundred fifty-five thousand, eight hundred forty".