1897387786849 has 3 divisors (see below), whose sum is σ = 1897389164307. Its totient is φ = 1897386409392.

The previous prime is 1897387786799. The next prime is 1897387786883. The reversal of 1897387786849 is 9486877837981.

The square root of 1897387786849 is 1377457.

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., 382597917025 + 1514789869824 = 618545^2 + 1230768^2 .

It is not a de Polignac number, because 1897387786849 - 2²¹ = 1897385689697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1897387786549) 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, 688729 + ... + 2066185.

It is an arithmetic number, because the mean of its divisors is an integer number (632463054769).

Almost surely, 2^{1897387786849} is an apocalyptic number.

1897387786849 is the 1377457-th square number.

1897387786849 is the 688729-th centered octagonal number.

It is an amenable number.

1897387786849 is a deficient number, since it is larger than the sum of its proper divisors (1377458).

1897387786849 is an frugal number, since it uses more digits than its factorization.

1897387786849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2754914 (or 1377457 counting only the distinct ones).

The product of its digits is 8193540096, while the sum is 85.

The spelling of 1897387786849 in words is "one trillion, eight hundred ninety-seven billion, three hundred eighty-seven million, seven hundred eighty-six thousand, eight hundred forty-nine".