212881639 has 4 divisors (see below), whose sum is σ = 214989480. Its totient is φ = 210773800.

The previous prime is 212881631. The next prime is 212881661. The reversal of 212881639 is 936188212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 212881639 - 2³ = 212881631 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 (212881631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1053769 + ... + 1053970.

It is an arithmetic number, because the mean of its divisors is an integer number (53747370).

Almost surely, 2^212881639 is an apocalyptic number.

212881639 is a deficient number, since it is larger than the sum of its proper divisors (2107841).

212881639 is a wasteful number, since it uses less digits than its factorization.

212881639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2107840.

The product of its digits is 41472, while the sum is 40.

The square root of 212881639 is about 14590.4639748022. The cubic root of 212881639 is about 597.0986213213.

The spelling of 212881639 in words is "two hundred twelve million, eight hundred eighty-one thousand, six hundred thirty-nine".