20120840 has 32 divisors (see below), whose sum is σ = 45399960. Its totient is φ = 8025600.

The previous prime is 20120839. The next prime is 20120851. The reversal of 20120840 is 4802102.

It can be written as a sum of positive squares in 4 ways, for example, as 12292036 + 7828804 = 3506^2 + 2798^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26060 + ... + 26820.

Almost surely, 2^20120840 is an apocalyptic number.

20120840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20120840 is an abundant number, since it is smaller than the sum of its proper divisors (25279120).

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

20120840 is a wasteful number, since it uses less digits than its factorization.

20120840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1433 (or 1429 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 20120840 is about 4485.6259317959. The cubic root of 20120840 is about 271.9873480274.

Adding to 20120840 its reverse (4802102), we get a palindrome (24922942).

The spelling of 20120840 in words is "twenty million, one hundred twenty thousand, eight hundred forty".