1261982691 has 12 divisors (see below), whose sum is σ = 1823675568. Its totient is φ = 840947184.

The previous prime is 1261982681. The next prime is 1261982719. The reversal of 1261982691 is 1962891621.

1261982691 is a `hidden beast` number, since 1 + 2 + 619 + 8 + 26 + 9 + 1 = 666.

It is not a de Polignac number, because 1261982691 - 2¹³ = 1261974499 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1261982671) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9055 + ... + 51048.

It is an arithmetic number, because the mean of its divisors is an integer number (151972964).

Almost surely, 2^1261982691 is an apocalyptic number.

1261982691 is a deficient number, since it is larger than the sum of its proper divisors (561692877).

1261982691 is a wasteful number, since it uses less digits than its factorization.

1261982691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62442 (or 62439 counting only the distinct ones).

The product of its digits is 93312, while the sum is 45.

The square root of 1261982691 is about 35524.3957161835. The cubic root of 1261982691 is about 1080.6485276697.

The spelling of 1261982691 in words is "one billion, two hundred sixty-one million, nine hundred eighty-two thousand, six hundred ninety-one".