1291440278 has 16 divisors (see below), whose sum is σ = 1946969136. Its totient is φ = 642458400.

The previous prime is 1291440277. The next prime is 1291440301. The reversal of 1291440278 is 8720441921.

It is a happy number.

It is a super-3 number, since 3×1291440278³ (a number of 28 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291440277) 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, 451553 + ... + 454403.

It is an arithmetic number, because the mean of its divisors is an integer number (121685571).

Almost surely, 2^1291440278 is an apocalyptic number.

1291440278 is a deficient number, since it is larger than the sum of its proper divisors (655528858).

1291440278 is a wasteful number, since it uses less digits than its factorization.

1291440278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3919.

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 1291440278 is about 35936.6147264875. The cubic root of 1291440278 is about 1088.9922166828.

The spelling of 1291440278 in words is "one billion, two hundred ninety-one million, four hundred forty thousand, two hundred seventy-eight".