1991249280 has 192 divisors, whose sum is σ = 6899602320. Its totient is φ = 529182720.

The previous prime is 1991249269. The next prime is 1991249297. The reversal of 1991249280 is 829421991.

1991249280 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (192).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3012150 + ... + 3012810.

Almost surely, 2^1991249280 is an apocalyptic number.

1991249280 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 1991249280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3449801160).

1991249280 is an abundant number, since it is smaller than the sum of its proper divisors (4908353040).

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

1991249280 is a wasteful number, since it uses less digits than its factorization.

1991249280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1209 (or 1194 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 45.

The square root of 1991249280 is about 44623.4162744181. The cubic root of 1991249280 is about 1258.0808273459.

The spelling of 1991249280 in words is "one billion, nine hundred ninety-one million, two hundred forty-nine thousand, two hundred eighty".