1491187823 has 8 divisors (see below), whose sum is σ = 1539755520. Its totient is φ = 1442649240.

The previous prime is 1491187813. The next prime is 1491187829. The reversal of 1491187823 is 3287811941.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1491187823 - 2⁸ = 1491187567 is a prime.

It is a super-2 number, since 2×1491187823² = 4447282246926958658, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1491187829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 153608 + ... + 163026.

It is an arithmetic number, because the mean of its divisors is an integer number (192469440).

Almost surely, 2^1491187823 is an apocalyptic number.

1491187823 is a deficient number, since it is larger than the sum of its proper divisors (48567697).

1491187823 is an equidigital number, since it uses as much as digits as its factorization.

1491187823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14557.

The product of its digits is 96768, while the sum is 44.

The square root of 1491187823 is about 38615.9011677832. The cubic root of 1491187823 is about 1142.4681885398.

The spelling of 1491187823 in words is "one billion, four hundred ninety-one million, one hundred eighty-seven thousand, eight hundred twenty-three".