1288660981 has 8 divisors (see below), whose sum is σ = 1296999000. Its totient is φ = 1280348160.

The previous prime is 1288660973. The next prime is 1288661009. The reversal of 1288660981 is 1890668821.

It can be written as a sum of positive squares in 4 ways, for example, as 293573956 + 995087025 = 17134^2 + 31545^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1288660981 - 2³ = 1288660973 is a prime.

It is a super-2 number, since 2×1288660981² = 3321294247903764722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1288660081) 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, 102255 + ... + 114163.

It is an arithmetic number, because the mean of its divisors is an integer number (162124875).

Almost surely, 2^1288660981 is an apocalyptic number.

It is an amenable number.

1288660981 is a deficient number, since it is larger than the sum of its proper divisors (8338019).

1288660981 is a wasteful number, since it uses less digits than its factorization.

1288660981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12599.

The product of its (nonzero) digits is 331776, while the sum is 49.

The square root of 1288660981 is about 35897.9244664646. The cubic root of 1288660981 is about 1088.2104521551.

The spelling of 1288660981 in words is "one billion, two hundred eighty-eight million, six hundred sixty thousand, nine hundred eighty-one".