12491861 has 4 divisors (see below), whose sum is σ = 12502752. Its totient is φ = 12480972.

The previous prime is 12491851. The next prime is 12491867. The reversal of 12491861 is 16819421.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 12491861 - 2¹⁰ = 12490837 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 (12491867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3491 + ... + 6096.

It is an arithmetic number, because the mean of its divisors is an integer number (3125688).

Almost surely, 2^12491861 is an apocalyptic number.

It is an amenable number.

12491861 is a deficient number, since it is larger than the sum of its proper divisors (10891).

12491861 is an equidigital number, since it uses as much as digits as its factorization.

12491861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10890.

The product of its digits is 3456, while the sum is 32.

The square root of 12491861 is about 3534.3826900889. The cubic root of 12491861 is about 232.0290602222.

The spelling of 12491861 in words is "twelve million, four hundred ninety-one thousand, eight hundred sixty-one".