285131820 has 48 divisors (see below), whose sum is σ = 845335008. Its totient is φ = 71562240.

The previous prime is 285131813. The next prime is 285131887. The reversal of 285131820 is 28131582.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 138751 + ... + 140790.

It is an arithmetic number, because the mean of its divisors is an integer number (17611146).

Almost surely, 2^285131820 is an apocalyptic number.

285131820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

285131820 is an abundant number, since it is smaller than the sum of its proper divisors (560203188).

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

285131820 is a wasteful number, since it uses less digits than its factorization.

285131820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279570 (or 279568 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 30.

The square root of 285131820 is about 16885.8467362463. The cubic root of 285131820 is about 658.1858813421.

The spelling of 285131820 in words is "two hundred eighty-five million, one hundred thirty-one thousand, eight hundred twenty".