1261478650 has 12 divisors (see below), whose sum is σ = 2346350382. Its totient is φ = 504591440.

The previous prime is 1261478639. The next prime is 1261478651. The reversal of 1261478650 is 568741621.

It can be written as a sum of positive squares in 3 ways, for example, as 943534089 + 317944561 = 30717^2 + 17831^2 .

It is not an unprimeable number, because it can be changed into a prime (1261478651) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12614737 + ... + 12614836.

Almost surely, 2^1261478650 is an apocalyptic number.

1261478650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1261478650 is a deficient number, since it is larger than the sum of its proper divisors (1084871732).

1261478650 is a wasteful number, since it uses less digits than its factorization.

1261478650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25229585 (or 25229580 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 40.

The square root of 1261478650 is about 35517.3007138775. The cubic root of 1261478650 is about 1080.5046367109.

The spelling of 1261478650 in words is "one billion, two hundred sixty-one million, four hundred seventy-eight thousand, six hundred fifty".