1665536656213 has 4 divisors (see below), whose sum is σ = 1665640179648. Its totient is φ = 1665433132780.

The previous prime is 1665536656207. The next prime is 1665536656261. The reversal of 1665536656213 is 3126566355661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1665536656213 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 (1665536656913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51737581 + ... + 51769762.

It is an arithmetic number, because the mean of its divisors is an integer number (416410044912).

Almost surely, 2^{1665536656213} is an apocalyptic number.

It is an amenable number.

1665536656213 is a deficient number, since it is larger than the sum of its proper divisors (103523435).

1665536656213 is a wasteful number, since it uses less digits than its factorization.

1665536656213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103523434.

The product of its digits is 17496000, while the sum is 55.

The spelling of 1665536656213 in words is "one trillion, six hundred sixty-five billion, five hundred thirty-six million, six hundred fifty-six thousand, two hundred thirteen".