1231556141 has 2 divisors, whose sum is σ = 1231556142. Its totient is φ = 1231556140.

The previous prime is 1231556119. The next prime is 1231556153. The reversal of 1231556141 is 1416551321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1023360100 + 208196041 = 31990^2 + 14429^2 .

It is an emirp because it is prime and its reverse (1416551321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1231556141 - 2¹⁸ = 1231293997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231556111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615778070 + 615778071.

It is an arithmetic number, because the mean of its divisors is an integer number (615778071).

Almost surely, 2^1231556141 is an apocalyptic number.

It is an amenable number.

1231556141 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231556141 is an equidigital number, since it uses as much as digits as its factorization.

1231556141 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3600, while the sum is 29.

The square root of 1231556141 is about 35093.5341765403. The cubic root of 1231556141 is about 1071.8929258007.

The spelling of 1231556141 in words is "one billion, two hundred thirty-one million, five hundred fifty-six thousand, one hundred forty-one".