1986388628449 has 3 divisors (see below), whose sum is σ = 1986390037843. Its totient is φ = 1986387219056.

The previous prime is 1986388628447. The next prime is 1986388628467. The reversal of 1986388628449 is 9448268836891.

It is a happy number.

The square root of 1986388628449 is 1409393.

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 can be written as a sum of positive squares in only one way, i.e., 797922360225 + 1188466268224 = 893265^2 + 1090168^2 .

It is not a de Polignac number, because 1986388628449 - 2¹ = 1986388628447 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1986388628447) 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, 704697 + ... + 2114089.

Almost surely, 2^{1986388628449} is an apocalyptic number.

1986388628449 is the 1409393-rd square number.

1986388628449 is the 704697-th centered octagonal number.

It is an amenable number.

1986388628449 is a deficient number, since it is larger than the sum of its proper divisors (1409394).

1986388628449 is an frugal number, since it uses more digits than its factorization.

1986388628449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2818786 (or 1409393 counting only the distinct ones).

The product of its digits is 1146617856, while the sum is 76.

The spelling of 1986388628449 in words is "one trillion, nine hundred eighty-six billion, three hundred eighty-eight million, six hundred twenty-eight thousand, four hundred forty-nine".