212153891 has 4 divisors (see below), whose sum is σ = 212325000. Its totient is φ = 211982784.

The previous prime is 212153861. The next prime is 212153917. The reversal of 212153891 is 198351212.

It is a happy number.

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 212153891 - 2⁶ = 212153827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212153861) 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, 83681 + ... + 86178.

It is an arithmetic number, because the mean of its divisors is an integer number (53081250).

Almost surely, 2^212153891 is an apocalyptic number.

212153891 is a deficient number, since it is larger than the sum of its proper divisors (171109).

212153891 is a wasteful number, since it uses less digits than its factorization.

212153891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171108.

The product of its digits is 4320, while the sum is 32.

The square root of 212153891 is about 14565.5034585146. The cubic root of 212153891 is about 596.4174393029.

The spelling of 212153891 in words is "two hundred twelve million, one hundred fifty-three thousand, eight hundred ninety-one".