1261978162 has 4 divisors (see below), whose sum is σ = 1892967246. Its totient is φ = 630989080.

The previous prime is 1261978117. The next prime is 1261978219. The reversal of 1261978162 is 2618791621.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 697012801 + 564965361 = 26401^2 + 23769^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315494539 + ... + 315494542.

Almost surely, 2^1261978162 is an apocalyptic number.

1261978162 is a deficient number, since it is larger than the sum of its proper divisors (630989084).

1261978162 is an equidigital number, since it uses as much as digits as its factorization.

1261978162 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630989083.

The product of its digits is 72576, while the sum is 43.

The square root of 1261978162 is about 35524.3319711997. The cubic root of 1261978162 is about 1080.6472349253.

The spelling of 1261978162 in words is "one billion, two hundred sixty-one million, nine hundred seventy-eight thousand, one hundred sixty-two".