1291046720 has 56 divisors (see below), whose sum is σ = 3106073544. Its totient is φ = 511082496.

The previous prime is 1291046719. The next prime is 1291046723. The reversal of 1291046720 is 276401921.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 21977344 + 1269069376 = 4688^2 + 35624^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291046723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10244 + ... + 51836.

It is an arithmetic number, because the mean of its divisors is an integer number (55465599).

Almost surely, 2^1291046720 is an apocalyptic number.

1291046720 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 1291046720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1553036772).

1291046720 is an abundant number, since it is smaller than the sum of its proper divisors (1815026824).

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

1291046720 is an equidigital number, since it uses as much as digits as its factorization.

1291046720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41707 (or 41697 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 1291046720 is about 35931.1385847986. The cubic root of 1291046720 is about 1088.8815843526.

The spelling of 1291046720 in words is "one billion, two hundred ninety-one million, forty-six thousand, seven hundred twenty".