212134857561 has 81 divisors (see below), whose sum is σ = 358219304989. Its totient is φ = 120856454400.

The previous prime is 212134857553. The next prime is 212134857577. The reversal of 212134857561 is 165758431212.

The square root of 212134857561 is 460581.

It is a perfect power (a square), and thus also a powerful number.

212134857561 is a `hidden beast` number, since 2 + 1 + 2 + 1 + 3 + 4 + 85 + 7 + 561 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 759278025 + 211375579536 = 27555^2 + 459756^2 .

It is not a de Polignac number, because 212134857561 - 2³ = 212134857553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212134857541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 258385531 + ... + 258386351.

Almost surely, 2^212134857561 is an apocalyptic number.

212134857561 is the 460581-st square number.

212134857561 is the 230291-st centered octagonal number.

It is an amenable number.

212134857561 is a deficient number, since it is larger than the sum of its proper divisors (146084447428).

212134857561 is an equidigital number, since it uses as much as digits as its factorization.

212134857561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1704 (or 852 counting only the distinct ones).

The product of its digits is 403200, while the sum is 45.

The spelling of 212134857561 in words is "two hundred twelve billion, one hundred thirty-four million, eight hundred fifty-seven thousand, five hundred sixty-one".