20640460 has 48 divisors (see below), whose sum is σ = 47224800. Its totient is φ = 7547904.

The previous prime is 20640449. The next prime is 20640469. The reversal of 20640460 is 6404602.

It is not an unprimeable number, because it can be changed into a prime (20640469) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10084 + ... + 11956.

It is an arithmetic number, because the mean of its divisors is an integer number (983850).

Almost surely, 2^20640460 is an apocalyptic number.

20640460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20640460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23612400).

20640460 is an abundant number, since it is smaller than the sum of its proper divisors (26584340).

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

20640460 is a wasteful number, since it uses less digits than its factorization.

20640460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1930 (or 1928 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 20640460 is about 4543.1773022853. The cubic root of 20640460 is about 274.3088318086.

The spelling of 20640460 in words is "twenty million, six hundred forty thousand, four hundred sixty".