1285919820 has 96 divisors (see below), whose sum is σ = 4055567040. Its totient is φ = 338204160.

The previous prime is 1285919801. The next prime is 1285919849. The reversal of 1285919820 is 289195821.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23110 + ... + 55730.

It is an arithmetic number, because the mean of its divisors is an integer number (42245490).

Almost surely, 2^1285919820 is an apocalyptic number.

1285919820 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 1285919820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2027783520).

1285919820 is an abundant number, since it is smaller than the sum of its proper divisors (2769647220).

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

1285919820 is a wasteful number, since it uses less digits than its factorization.

1285919820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32712 (or 32704 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 45.

The square root of 1285919820 is about 35859.7242041821. The cubic root of 1285919820 is about 1087.4383127911.

The spelling of 1285919820 in words is "one billion, two hundred eighty-five million, nine hundred nineteen thousand, eight hundred twenty".