1491081840 has 60 divisors (see below), whose sum is σ = 5007552264. Its totient is φ = 397621632.

The previous prime is 1491081811. The next prime is 1491081853. The reversal of 1491081840 is 481801941.

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1491081795 and 1491081804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1034754 + ... + 1036193.

Almost surely, 2^1491081840 is an apocalyptic number.

1491081840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1491081840 is an abundant number, since it is smaller than the sum of its proper divisors (3516470424).

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

1491081840 is a wasteful number, since it uses less digits than its factorization.

1491081840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2070966 (or 2070957 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 1491081840 is about 38614.5288719156. The cubic root of 1491081840 is about 1142.4411217338.

The spelling of 1491081840 in words is "one billion, four hundred ninety-one million, eighty-one thousand, eight hundred forty".