1491118691 has 2 divisors, whose sum is σ = 1491118692. Its totient is φ = 1491118690.

The previous prime is 1491118679. The next prime is 1491118711. The reversal of 1491118691 is 1968111941.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1491118691 - 2³⁰ = 417376867 is a prime.

It is not a weakly prime, because it can be changed into another prime (1491111691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 745559345 + 745559346.

It is an arithmetic number, because the mean of its divisors is an integer number (745559346).

Almost surely, 2^1491118691 is an apocalyptic number.

1491118691 is a deficient number, since it is larger than the sum of its proper divisors (1).

1491118691 is an equidigital number, since it uses as much as digits as its factorization.

1491118691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 41.

The square root of 1491118691 is about 38615.0060339242. The cubic root of 1491118691 is about 1142.4505331892.

The spelling of 1491118691 in words is "one billion, four hundred ninety-one million, one hundred eighteen thousand, six hundred ninety-one".