211055661561 has 8 divisors (see below), whose sum is σ = 281412355264. Its totient is φ = 140701371120.

The previous prime is 211055661511. The next prime is 211055661569. The reversal of 211055661561 is 165166550112.

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

It is not a de Polignac number, because 211055661561 - 2¹⁹ = 211055137273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (211055661569) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 384805 + ... + 755106.

It is an arithmetic number, because the mean of its divisors is an integer number (35176544408).

Almost surely, 2^211055661561 is an apocalyptic number.

It is an amenable number.

211055661561 is a deficient number, since it is larger than the sum of its proper divisors (70356693703).

211055661561 is a wasteful number, since it uses less digits than its factorization.

211055661561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1201631.

The product of its (nonzero) digits is 54000, while the sum is 39.

The spelling of 211055661561 in words is "two hundred eleven billion, fifty-five million, six hundred sixty-one thousand, five hundred sixty-one".