20586640 has 40 divisors (see below), whose sum is σ = 48088440. Its totient is φ = 8196096.

The previous prime is 20586617. The next prime is 20586641. The reversal of 20586640 is 4668502.

It can be written as a sum of positive squares in 4 ways, for example, as 659344 + 19927296 = 812^2 + 4464^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (20586641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21696 + ... + 22624.

It is an arithmetic number, because the mean of its divisors is an integer number (1202211).

Almost surely, 2^20586640 is an apocalyptic number.

20586640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20586640 is an abundant number, since it is smaller than the sum of its proper divisors (27501800).

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

20586640 is a wasteful number, since it uses less digits than its factorization.

20586640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1219 (or 1213 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 20586640 is about 4537.2502686098. The cubic root of 20586640 is about 274.0702041856.

The spelling of 20586640 in words is "twenty million, five hundred eighty-six thousand, six hundred forty".