1261787144 has 8 divisors (see below), whose sum is σ = 2365850910. Its totient is φ = 630893568.

The previous prime is 1261787143. The next prime is 1261787147. The reversal of 1261787144 is 4417871621.

It can be written as a sum of positive squares in only one way, i.e., 797384644 + 464402500 = 28238^2 + 21550^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (1261787143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78861689 + ... + 78861704.

Almost surely, 2^1261787144 is an apocalyptic number.

It is an amenable number.

1261787144 is a deficient number, since it is larger than the sum of its proper divisors (1104063766).

1261787144 is a wasteful number, since it uses less digits than its factorization.

1261787144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157723399 (or 157723395 counting only the distinct ones).

The product of its digits is 75264, while the sum is 41.

The square root of 1261787144 is about 35521.6433178422. The cubic root of 1261787144 is about 1080.5927084959.

The spelling of 1261787144 in words is "one billion, two hundred sixty-one million, seven hundred eighty-seven thousand, one hundred forty-four".