1285820100 has 54 divisors (see below), whose sum is σ = 4030334490. Its totient is φ = 342885120.

The previous prime is 1285820089. The next prime is 1285820131. The reversal of 1285820100 is 10285821.

It can be written as a sum of positive squares in 3 ways, for example, as 1887876 + 1283932224 = 1374^2 + 35832^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 713445 + ... + 715244.

Almost surely, 2^1285820100 is an apocalyptic number.

1285820100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1285820100 is an abundant number, since it is smaller than the sum of its proper divisors (2744514390).

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

1285820100 is a wasteful number, since it uses less digits than its factorization.

1285820100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1428709 (or 1428699 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The square root of 1285820100 is about 35858.3337593927. Note that the first 3 decimals coincide. The cubic root of 1285820100 is about 1087.4102026528.

The spelling of 1285820100 in words is "one billion, two hundred eighty-five million, eight hundred twenty thousand, one hundred".