18661437894827 has 24 divisors (see below), whose sum is σ = 24608489547600. Its totient is φ = 13987983514176.

The previous prime is 18661437894823. The next prime is 18661437894829. The reversal of 18661437894827 is 72849873416681.

It is a happy number.

It is not a de Polignac number, because 18661437894827 - 2² = 18661437894823 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18661437894823) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 770930552 + ... + 770954757.

It is an arithmetic number, because the mean of its divisors is an integer number (1025353731150).

Almost surely, 2^{18661437894827} is an apocalyptic number.

18661437894827 is a deficient number, since it is larger than the sum of its proper divisors (5947051652773).

18661437894827 is a wasteful number, since it uses less digits than its factorization.

18661437894827 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1541885355 (or 1541885348 counting only the distinct ones).

The product of its digits is 780337152, while the sum is 74.

The spelling of 18661437894827 in words is "eighteen trillion, six hundred sixty-one billion, four hundred thirty-seven million, eight hundred ninety-four thousand, eight hundred twenty-seven".