1291668720 has 80 divisors (see below), whose sum is σ = 4008076800. Its totient is φ = 344109312.

The previous prime is 1291668629. The next prime is 1291668727. The reversal of 1291668720 is 278661921.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291668727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 333837 + ... + 337683.

It is an arithmetic number, because the mean of its divisors is an integer number (50100960).

Almost surely, 2^1291668720 is an apocalyptic number.

1291668720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1291668720 is an abundant number, since it is smaller than the sum of its proper divisors (2716408080).

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

1291668720 is a wasteful number, since it uses less digits than its factorization.

1291668720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5262 (or 5256 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 42.

The square root of 1291668720 is about 35939.7929877177. The cubic root of 1291668720 is about 1089.0564232635.

The spelling of 1291668720 in words is "one billion, two hundred ninety-one million, six hundred sixty-eight thousand, seven hundred twenty".