1361666573 has 4 divisors (see below), whose sum is σ = 1361740380. Its totient is φ = 1361592768.

The previous prime is 1361666557. The next prime is 1361666617. The reversal of 1361666573 is 3756661631.

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 2 ways, for example, as 1135555204 + 226111369 = 33698^2 + 15037^2 .

It is a cyclic number.

It is not a de Polignac number, because 1361666573 - 2⁴ = 1361666557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1361666473) 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, 17843 + ... + 55151.

It is an arithmetic number, because the mean of its divisors is an integer number (340435095).

Almost surely, 2^1361666573 is an apocalyptic number.

It is an amenable number.

1361666573 is a deficient number, since it is larger than the sum of its proper divisors (73807).

1361666573 is an equidigital number, since it uses as much as digits as its factorization.

1361666573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73806.

The product of its digits is 408240, while the sum is 44.

The square root of 1361666573 is about 36900.7665638534. The cubic root of 1361666573 is about 1108.3840276409.

The spelling of 1361666573 in words is "one billion, three hundred sixty-one million, six hundred sixty-six thousand, five hundred seventy-three".