213104334111661 has 4 divisors (see below), whose sum is σ = 213128492870524. Its totient is φ = 213080175352800.

The previous prime is 213104334111649. The next prime is 213104334111679. The reversal of 213104334111661 is 166111433401312.

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 95540732956036 + 117563601155625 = 9774494^2 + 10842675^2 .

It is a cyclic number.

It is not a de Polignac number, because 213104334111661 - 2¹¹ = 213104334109613 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 213104334111661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213104334111631) 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, 12079366200 + ... + 12079383841.

It is an arithmetic number, because the mean of its divisors is an integer number (53282123217631).

Almost surely, 2^{213104334111661} is an apocalyptic number.

It is an amenable number.

213104334111661 is a deficient number, since it is larger than the sum of its proper divisors (24158758863).

213104334111661 is an equidigital number, since it uses as much as digits as its factorization.

213104334111661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24158758862.

The product of its (nonzero) digits is 31104, while the sum is 37.

Adding to 213104334111661 its reverse (166111433401312), we get a palindrome (379215767512973).

The spelling of 213104334111661 in words is "two hundred thirteen trillion, one hundred four billion, three hundred thirty-four million, one hundred eleven thousand, six hundred sixty-one".