211543656461 has 4 divisors (see below), whose sum is σ = 211547839932. Its totient is φ = 211539472992.

The previous prime is 211543656419. The next prime is 211543656553. The reversal of 211543656461 is 164656345112.

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 88012495561 + 123531160900 = 296669^2 + 351470^2 .

It is a cyclic number.

It is not a de Polignac number, because 211543656461 - 2⁶ = 211543656397 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 (211543656761) 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, 2014946 + ... + 2117331.

It is an arithmetic number, because the mean of its divisors is an integer number (52886959983).

Almost surely, 2^211543656461 is an apocalyptic number.

It is an amenable number.

211543656461 is a deficient number, since it is larger than the sum of its proper divisors (4183471).

211543656461 is an equidigital number, since it uses as much as digits as its factorization.

211543656461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4183470.

The product of its digits is 518400, while the sum is 44.

The spelling of 211543656461 in words is "two hundred eleven billion, five hundred forty-three million, six hundred fifty-six thousand, four hundred sixty-one".