1285781400 has 144 divisors (see below), whose sum is σ = 4572196200. Its totient is φ = 322698240.

The previous prime is 1285781369. The next prime is 1285781407. The reversal of 1285781400 is 41875821.

1285781400 is a `hidden beast` number, since 128 + 57 + 81 + 400 = 666.

1285781400 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1285781407) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 9591 + ... + 51609.

Almost surely, 2^1285781400 is an apocalyptic number.

1285781400 is a gapful number since it is divisible by the number (10) 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 1285781400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2286098100).

1285781400 is an abundant number, since it is smaller than the sum of its proper divisors (3286414800).

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

1285781400 is a wasteful number, since it uses less digits than its factorization.

1285781400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42058 (or 42046 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 36.

The square root of 1285781400 is about 35857.7941318202. The cubic root of 1285781400 is about 1087.3992930922.

The spelling of 1285781400 in words is "one billion, two hundred eighty-five million, seven hundred eighty-one thousand, four hundred".