20640582 has 40 divisors (see below), whose sum is σ = 46736976. Its totient is φ = 6807888.

The previous prime is 20640577. The next prime is 20640583. The reversal of 20640582 is 28504602.

20640582 is a `hidden beast` number, since 20 + 64 + 0 + 582 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20640583) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 16068 + ... + 17304.

Almost surely, 2^20640582 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20640582, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23368488).

20640582 is an abundant number, since it is smaller than the sum of its proper divisors (26096394).

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

20640582 is a wasteful number, since it uses less digits than its factorization.

20640582 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1354 (or 1345 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 20640582 is about 4543.1907289921. The cubic root of 20640582 is about 274.3093722618.

20640582 divided by its sum of digits (27) gives a triangular number (764466 = T₁₂₃₆).

The spelling of 20640582 in words is "twenty million, six hundred forty thousand, five hundred eighty-two".