1231171203261 has 16 divisors (see below), whose sum is σ = 1654626541568. Its totient is φ = 814249422000.

The previous prime is 1231171203259. The next prime is 1231171203281. The reversal of 1231171203261 is 1623021711321.

It is not a de Polignac number, because 1231171203261 - 2¹ = 1231171203259 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231171203281) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4614066 + ... + 4873596.

It is an arithmetic number, because the mean of its divisors is an integer number (103414158848).

Almost surely, 2^{1231171203261} is an apocalyptic number.

It is an amenable number.

1231171203261 is a deficient number, since it is larger than the sum of its proper divisors (423455338307).

1231171203261 is a wasteful number, since it uses less digits than its factorization.

1231171203261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272112.

The product of its (nonzero) digits is 3024, while the sum is 30.

Adding to 1231171203261 its reverse (1623021711321), we get a palindrome (2854192914582).

The spelling of 1231171203261 in words is "one trillion, two hundred thirty-one billion, one hundred seventy-one million, two hundred three thousand, two hundred sixty-one".