212509138 has 4 divisors (see below), whose sum is σ = 318763710. Its totient is φ = 106254568.

The previous prime is 212509111. The next prime is 212509147. The reversal of 212509138 is 831905212.

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

It can be written as a sum of positive squares in only one way, i.e., 120406729 + 92102409 = 10973^2 + 9597^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 53127283 + ... + 53127286.

Almost surely, 2^212509138 is an apocalyptic number.

212509138 is a deficient number, since it is larger than the sum of its proper divisors (106254572).

212509138 is a wasteful number, since it uses less digits than its factorization.

212509138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106254571.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 212509138 is about 14577.6931645580. The cubic root of 212509138 is about 596.7501496053.

The spelling of 212509138 in words is "two hundred twelve million, five hundred nine thousand, one hundred thirty-eight".