1278140581 has 2 divisors, whose sum is σ = 1278140582. Its totient is φ = 1278140580.

The previous prime is 1278140569. The next prime is 1278140587. The reversal of 1278140581 is 1850418721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1158040900 + 120099681 = 34030^2 + 10959^2 .

It is a cyclic number.

It is not a de Polignac number, because 1278140581 - 2⁷ = 1278140453 is a prime.

It is a super-2 number, since 2×1278140581² = 3267286689598035122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1278140581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1278140587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639070290 + 639070291.

It is an arithmetic number, because the mean of its divisors is an integer number (639070291).

Almost surely, 2^1278140581 is an apocalyptic number.

It is an amenable number.

1278140581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278140581 is an equidigital number, since it uses as much as digits as its factorization.

1278140581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17920, while the sum is 37.

The square root of 1278140581 is about 35751.0920252795. The cubic root of 1278140581 is about 1085.2410377153.

It can be divided in two parts, 1278140 and 581, that added together give a palindrome (1278721).

The spelling of 1278140581 in words is "one billion, two hundred seventy-eight million, one hundred forty thousand, five hundred eighty-one".