20427840 has 168 divisors, whose sum is σ = 72393048. Its totient is φ = 5283840.

The previous prime is 20427833. The next prime is 20427859. The reversal of 20427840 is 4872402.

It can be written as a sum of positive squares in 4 ways, for example, as 1557504 + 18870336 = 1248^2 + 4344^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 117994 + ... + 118166.

It is an arithmetic number, because the mean of its divisors is an integer number (430911).

Almost surely, 2^20427840 is an apocalyptic number.

20427840 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 20427840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36196524).

20427840 is an abundant number, since it is smaller than the sum of its proper divisors (51965208).

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

20427840 is a wasteful number, since it uses less digits than its factorization.

20427840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 237 (or 224 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 27.

The square root of 20427840 is about 4519.7168052877. The cubic root of 20427840 is about 273.3636822670.

The spelling of 20427840 in words is "twenty million, four hundred twenty-seven thousand, eight hundred forty".