212135639 has 4 divisors (see below), whose sum is σ = 224614224. Its totient is φ = 199657056.

The previous prime is 212135629. The next prime is 212135687. The reversal of 212135639 is 936531212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212135639 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 (212135629) 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 3 ways as a sum of consecutive naturals, for example, 6239267 + ... + 6239300.

It is an arithmetic number, because the mean of its divisors is an integer number (56153556).

Almost surely, 2^212135639 is an apocalyptic number.

212135639 is a deficient number, since it is larger than the sum of its proper divisors (12478585).

212135639 is a wasteful number, since it uses less digits than its factorization.

212135639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12478584.

The product of its digits is 9720, while the sum is 32.

The square root of 212135639 is about 14564.8768961499. The cubic root of 212135639 is about 596.4003351728.

The spelling of 212135639 in words is "two hundred twelve million, one hundred thirty-five thousand, six hundred thirty-nine".