1231847261 has 2 divisors, whose sum is σ = 1231847262. Its totient is φ = 1231847260.

The previous prime is 1231847249. The next prime is 1231847269. The reversal of 1231847261 is 1627481321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1071318361 + 160528900 = 32731^2 + 12670^2 .

It is an emirp because it is prime and its reverse (1627481321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1231847261 - 2²² = 1227652957 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231847269) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615923630 + 615923631.

It is an arithmetic number, because the mean of its divisors is an integer number (615923631).

Almost surely, 2^1231847261 is an apocalyptic number.

1231847261 is the 18761-st centered heptagonal number.

It is an amenable number.

1231847261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231847261 is an equidigital number, since it uses as much as digits as its factorization.

1231847261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 35.

The square root of 1231847261 is about 35097.6817040670. The cubic root of 1231847261 is about 1071.9773785440.

The spelling of 1231847261 in words is "one billion, two hundred thirty-one million, eight hundred forty-seven thousand, two hundred sixty-one".