1491784509 has 16 divisors (see below), whose sum is σ = 2036750144. Its totient is φ = 970704000.

The previous prime is 1491784507. The next prime is 1491784517. The reversal of 1491784509 is 9054871941.

It is not a de Polignac number, because 1491784509 - 2¹ = 1491784507 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1491784501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 229119 + ... + 235539.

It is an arithmetic number, because the mean of its divisors is an integer number (127296884).

Almost surely, 2^1491784509 is an apocalyptic number.

It is an amenable number.

1491784509 is a deficient number, since it is larger than the sum of its proper divisors (544965635).

1491784509 is a wasteful number, since it uses less digits than its factorization.

1491784509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8268.

The product of its (nonzero) digits is 362880, while the sum is 48.

The square root of 1491784509 is about 38623.6263056694. The cubic root of 1491784509 is about 1142.6205511638.

The spelling of 1491784509 in words is "one billion, four hundred ninety-one million, seven hundred eighty-four thousand, five hundred nine".