991747015 has 24 divisors (see below), whose sum is σ = 1386741600. Its totient is φ = 678904128.

The previous prime is 991747013. The next prime is 991747021. The reversal of 991747015 is 510747199.

It is not a de Polignac number, because 991747015 - 2¹ = 991747013 is a prime.

It is a super-2 number, since 2×991747015² = 1967124283522820450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991747013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 156886 + ... + 163084.

It is an arithmetic number, because the mean of its divisors is an integer number (57780900).

Almost surely, 2^991747015 is an apocalyptic number.

991747015 is a deficient number, since it is larger than the sum of its proper divisors (394994585).

991747015 is a wasteful number, since it uses less digits than its factorization.

991747015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6871 (or 6864 counting only the distinct ones).

The product of its (nonzero) digits is 79380, while the sum is 43.

The square root of 991747015 is about 31492.0150990692. The cubic root of 991747015 is about 997.2414021353.

The spelling of 991747015 in words is "nine hundred ninety-one million, seven hundred forty-seven thousand, fifteen".