213121004516666 has 8 divisors (see below), whose sum is σ = 319718298319860. Its totient is φ = 106548238410048.

The previous prime is 213121004516627. The next prime is 213121004516699. The reversal of 213121004516666 is 666615400121312.

It can be written as a sum of positive squares in 2 ways, for example, as 199967173950625 + 13153830566041 = 14140975^2 + 3626821^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6131902421 + ... + 6131937176.

Almost surely, 2^{213121004516666} is an apocalyptic number.

213121004516666 is a deficient number, since it is larger than the sum of its proper divisors (106597293803194).

213121004516666 is a wasteful number, since it uses less digits than its factorization.

213121004516666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12263848288.

The product of its (nonzero) digits is 311040, while the sum is 44.

Adding to 213121004516666 its reverse (666615400121312), we get a palindrome (879736404637978).

The spelling of 213121004516666 in words is "two hundred thirteen trillion, one hundred twenty-one billion, four million, five hundred sixteen thousand, six hundred sixty-six".