20640834 has 12 divisors (see below), whose sum is σ = 44721846. Its totient is φ = 6880272.

The previous prime is 20640833. The next prime is 20640847. The reversal of 20640834 is 43804602.

It can be written as a sum of positive squares in only one way, i.e., 17665209 + 2975625 = 4203^2 + 1725^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20640798 and 20640807.

It is not an unprimeable number, because it can be changed into a prime (20640833) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 573339 + ... + 573374.

Almost surely, 2^20640834 is an apocalyptic number.

20640834 is an abundant number, since it is smaller than the sum of its proper divisors (24081012).

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

20640834 is a wasteful number, since it uses less digits than its factorization.

20640834 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1146721 (or 1146718 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 20640834 is about 4543.2184627200. The cubic root of 20640834 is about 274.3104886012.

The spelling of 20640834 in words is "twenty million, six hundred forty thousand, eight hundred thirty-four".