28991181840 has 40 divisors (see below), whose sum is σ = 89872664448. Its totient is φ = 7730981760.

The previous prime is 28991181823. The next prime is 28991181851. The reversal of 28991181840 is 4818119982.

It is a tau number, because it is divible by the number of its divisors (40).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60398056 + ... + 60398535.

Almost surely, 2^28991181840 is an apocalyptic number.

28991181840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28991181840 is an abundant number, since it is smaller than the sum of its proper divisors (60881482608).

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

28991181840 is a wasteful number, since it uses less digits than its factorization.

28991181840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120796607 (or 120796601 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 51.

The spelling of 28991181840 in words is "twenty-eight billion, nine hundred ninety-one million, one hundred eighty-one thousand, eight hundred forty".