212861866010681 has 4 divisors (see below), whose sum is σ = 213234653867664. Its totient is φ = 212489078153700.

The previous prime is 212861866010663. The next prime is 212861866010683. The reversal of 212861866010681 is 186010668168212.

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 not a de Polignac number, because 212861866010681 - 2¹⁰ = 212861866009657 is a prime.

It is a super-2 number, since 2×212861866010681² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (212861866010683) 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, 186393927635 + ... + 186393928776.

It is an arithmetic number, because the mean of its divisors is an integer number (53308663466916).

Almost surely, 2^{212861866010681} is an apocalyptic number.

It is an amenable number.

212861866010681 is a deficient number, since it is larger than the sum of its proper divisors (372787856983).

212861866010681 is an equidigital number, since it uses as much as digits as its factorization.

212861866010681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372787856982.

The product of its (nonzero) digits is 2654208, while the sum is 56.

The spelling of 212861866010681 in words is "two hundred twelve trillion, eight hundred sixty-one billion, eight hundred sixty-six million, ten thousand, six hundred eighty-one".