1989900918 has 20 divisors (see below), whose sum is σ = 4458852420. Its totient is φ = 663300252.

The previous prime is 1989900911. The next prime is 1989900923. The reversal of 1989900918 is 8190099891.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1989900911) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 6141508 + ... + 6141831.

It is an arithmetic number, because the mean of its divisors is an integer number (222942621).

Almost surely, 2^1989900918 is an apocalyptic number.

1989900918 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1989900918 is an abundant number, since it is smaller than the sum of its proper divisors (2468951502).

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

1989900918 is a wasteful number, since it uses less digits than its factorization.

1989900918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12283353 (or 12283344 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 54.

The square root of 1989900918 is about 44608.3054822754. The cubic root of 1989900918 is about 1257.7967960375.

The spelling of 1989900918 in words is "one billion, nine hundred eighty-nine million, nine hundred thousand, nine hundred eighteen".