9131904720 has 120 divisors (see below), whose sum is σ = 30686596200. Its totient is φ = 2433696768.

The previous prime is 9131904713. The next prime is 9131904757. The reversal of 9131904720 is 274091319.

It is a Cunningham number, because it is equal to 95561²-1.

It can be written as a sum of positive squares in 4 ways, for example, as 312440976 + 8819463744 = 17676^2 + 93912^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1717426 + ... + 1722734.

It is an arithmetic number, because the mean of its divisors is an integer number (255721635).

Almost surely, 2^9131904720 is an apocalyptic number.

9131904720 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9131904720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15343298100).

9131904720 is an abundant number, since it is smaller than the sum of its proper divisors (21554691480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9131904720 is a wasteful number, since it uses less digits than its factorization.

9131904720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7717 (or 7708 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 9131904720 is about 95560.9999947677. Note that the first 5 decimals coincide. The cubic root of 9131904720 is about 2090.1965368469.

The spelling of 9131904720 in words is "nine billion, one hundred thirty-one million, nine hundred four thousand, seven hundred twenty".