1291434240 has 288 divisors, whose sum is σ = 4443296256. Its totient is φ = 318504960.

The previous prime is 1291434229. The next prime is 1291434259. The reversal of 1291434240 is 424341921.

1291434240 = 4170² + 4171² + ... + 4242².

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1291434198 and 1291434207.

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, 4765305 + ... + 4765575.

It is an arithmetic number, because the mean of its divisors is an integer number (15428112).

Almost surely, 2^1291434240 is an apocalyptic number.

1291434240 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 1291434240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2221648128).

1291434240 is an abundant number, since it is smaller than the sum of its proper divisors (3151862016).

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

1291434240 is a wasteful number, since it uses less digits than its factorization.

1291434240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385 (or 371 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 1291434240 is about 35936.5307173634. The cubic root of 1291434240 is about 1088.9905195221.

The spelling of 1291434240 in words is "one billion, two hundred ninety-one million, four hundred thirty-four thousand, two hundred forty".