1081861998 has 64 divisors (see below), whose sum is σ = 2571222528. Its totient is φ = 297031680.

The previous prime is 1081861969. The next prime is 1081862029. The reversal of 1081861998 is 8991681801.

It is a self number, because there is not a number n which added to its sum of digits gives 1081861998.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 110686 + ... + 120062.

It is an arithmetic number, because the mean of its divisors is an integer number (40175352).

Almost surely, 2^1081861998 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1081861998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1285611264).

1081861998 is an abundant number, since it is smaller than the sum of its proper divisors (1489360530).

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

1081861998 is a wasteful number, since it uses less digits than its factorization.

1081861998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9497.

The product of its (nonzero) digits is 248832, while the sum is 51.

The square root of 1081861998 is about 32891.6706477491. The cubic root of 1081861998 is about 1026.5748538846.

The spelling of 1081861998 in words is "one billion, eighty-one million, eight hundred sixty-one thousand, nine hundred ninety-eight".