1317091720 has 128 divisors (see below), whose sum is σ = 3494937600. Its totient is φ = 437342976.

The previous prime is 1317091709. The next prime is 1317091747. The reversal of 1317091720 is 271907131.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1673167 + ... + 1673953.

It is an arithmetic number, because the mean of its divisors is an integer number (27304200).

Almost surely, 2^1317091720 is an apocalyptic number.

1317091720 is a gapful number since it is divisible by the number (10) 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 1317091720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1747468800).

1317091720 is an abundant number, since it is smaller than the sum of its proper divisors (2177845880).

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

1317091720 is a wasteful number, since it uses less digits than its factorization.

1317091720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 987 (or 983 counting only the distinct ones).

The product of its (nonzero) digits is 2646, while the sum is 31.

The square root of 1317091720 is about 36291.7582930340. The cubic root of 1317091720 is about 1096.1550942007.

Adding to 1317091720 its reverse (271907131), we get a palindrome (1588998851).

The spelling of 1317091720 in words is "one billion, three hundred seventeen million, ninety-one thousand, seven hundred twenty".