20781860 has 24 divisors (see below), whose sum is σ = 47609856. Its totient is φ = 7556960.

The previous prime is 20781851. The next prime is 20781863. The reversal of 20781860 is 6818702.

It is not an unprimeable number, because it can be changed into a prime (20781863) 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, 47012 + ... + 47451.

It is an arithmetic number, because the mean of its divisors is an integer number (1983744).

Almost surely, 2^20781860 is an apocalyptic number.

20781860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20781860 is an abundant number, since it is smaller than the sum of its proper divisors (26827996).

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

20781860 is a wasteful number, since it uses less digits than its factorization.

20781860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94483 (or 94481 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 20781860 is about 4558.7125375483. The cubic root of 20781860 is about 274.9338022480.

The spelling of 20781860 in words is "twenty million, seven hundred eighty-one thousand, eight hundred sixty".