212857561 has 32 divisors (see below), whose sum is σ = 264695040. Its totient is φ = 167049216.

The previous prime is 212857553. The next prime is 212857573. The reversal of 212857561 is 165758212.

It is a cyclic number.

It is not a de Polignac number, because 212857561 - 2³ = 212857553 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 212857561.

It is not an unprimeable number, because it can be changed into a prime (212857591) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 929395 + ... + 929623.

It is an arithmetic number, because the mean of its divisors is an integer number (8271720).

Almost surely, 2^212857561 is an apocalyptic number.

It is an amenable number.

212857561 is a deficient number, since it is larger than the sum of its proper divisors (51837479).

212857561 is a wasteful number, since it uses less digits than its factorization.

212857561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433.

The product of its digits is 33600, while the sum is 37.

The square root of 212857561 is about 14589.6388234939. The cubic root of 212857561 is about 597.0761088385.

It can be divided in two parts, 21 and 2857561, that added together give a palindrome (2857582).

The spelling of 212857561 in words is "two hundred twelve million, eight hundred fifty-seven thousand, five hundred sixty-one".