9915951491 has 4 divisors (see below), whose sum is σ = 9967329672. Its totient is φ = 9864573312.

The previous prime is 9915951449. The next prime is 9915951587. The reversal of 9915951491 is 1941595199.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1941595199 = 19 ⋅102189221.

It is a cyclic number.

It is not a de Polignac number, because 9915951491 - 2⁶ = 9915951427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9915951421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25688801 + ... + 25689186.

It is an arithmetic number, because the mean of its divisors is an integer number (2491832418).

Almost surely, 2^9915951491 is an apocalyptic number.

9915951491 is a deficient number, since it is larger than the sum of its proper divisors (51378181).

9915951491 is a wasteful number, since it uses less digits than its factorization.

9915951491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51378180.

The product of its digits is 656100, while the sum is 53.

The square root of 9915951491 is about 99578.8707055869. The cubic root of 9915951491 is about 2148.3817995633.

The spelling of 9915951491 in words is "nine billion, nine hundred fifteen million, nine hundred fifty-one thousand, four hundred ninety-one".