1618866888409 has 3 divisors (see below), whose sum is σ = 1618868160757. Its totient is φ = 1618865616062.

The previous prime is 1618866888377. The next prime is 1618866888413. The reversal of 1618866888409 is 9048886688161.

The square root of 1618866888409 is 1272347.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 1618866888409 - 2⁵ = 1618866888377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1618866888479) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 636174 + ... + 1908520.

Almost surely, 2^{1618866888409} is an apocalyptic number.

1618866888409 is the 1272347-th square number.

1618866888409 is the 636174-th centered octagonal number.

It is an amenable number.

1618866888409 is a deficient number, since it is larger than the sum of its proper divisors (1272348).

1618866888409 is an frugal number, since it uses more digits than its factorization.

1618866888409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2544694 (or 1272347 counting only the distinct ones).

The product of its (nonzero) digits is 254803968, while the sum is 73.

The spelling of 1618866888409 in words is "one trillion, six hundred eighteen billion, eight hundred sixty-six million, eight hundred eighty-eight thousand, four hundred nine".