9951591 has 16 divisors (see below), whose sum is σ = 14426720. Its totient is φ = 6065280.

The previous prime is 9951587. The next prime is 9951637. The reversal of 9951591 is 1951599.

It is not a de Polignac number, because 9951591 - 2² = 9951587 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9951541) 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, 3081 + ... + 5421.

It is an arithmetic number, because the mean of its divisors is an integer number (901670).

Almost surely, 2^9951591 is an apocalyptic number.

9951591 is a deficient number, since it is larger than the sum of its proper divisors (4475129).

9951591 is a wasteful number, since it uses less digits than its factorization.

9951591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2466.

The product of its digits is 18225, while the sum is 39.

The square root of 9951591 is about 3154.6142394911. The cubic root of 9951591 is about 215.0952597522.

The spelling of 9951591 in words is "nine million, nine hundred fifty-one thousand, five hundred ninety-one".