1081891816 has 32 divisors (see below), whose sum is σ = 2102860800. Its totient is φ = 521277120.

The previous prime is 1081891793. The next prime is 1081891819. The reversal of 1081891816 is 6181981801.

It is a happy number.

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (1081891819) 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, 50146 + ... + 68398.

It is an arithmetic number, because the mean of its divisors is an integer number (65714400).

Almost surely, 2^1081891816 is an apocalyptic number.

It is an amenable number.

1081891816 is a deficient number, since it is larger than the sum of its proper divisors (1020968984).

1081891816 is a wasteful number, since it uses less digits than its factorization.

1081891816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18529 (or 18525 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 43.

The square root of 1081891816 is about 32892.1239204768. The cubic root of 1081891816 is about 1026.5842851946.

The spelling of 1081891816 in words is "one billion, eighty-one million, eight hundred ninety-one thousand, eight hundred sixteen".