1866851668537 has 4 divisors (see below), whose sum is σ = 1917307119076. Its totient is φ = 1816396218000.

The previous prime is 1866851668531. The next prime is 1866851668553. The reversal of 1866851668537 is 7358661586681.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1460752635456 + 406099033081 = 1208616^2 + 637259^2 .

It is a cyclic number.

It is not a de Polignac number, because 1866851668537 - 2¹¹ = 1866851666489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1866851668531) 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, 25227725214 + ... + 25227725287.

It is an arithmetic number, because the mean of its divisors is an integer number (479326779769).

Almost surely, 2^{1866851668537} is an apocalyptic number.

It is an amenable number.

1866851668537 is a deficient number, since it is larger than the sum of its proper divisors (50455450539).

1866851668537 is an equidigital number, since it uses as much as digits as its factorization.

1866851668537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50455450538.

The product of its digits is 348364800, while the sum is 70.

The spelling of 1866851668537 in words is "one trillion, eight hundred sixty-six billion, eight hundred fifty-one million, six hundred sixty-eight thousand, five hundred thirty-seven".