213169991 has 2 divisors, whose sum is σ = 213169992. Its totient is φ = 213169990.

The previous prime is 213169969. The next prime is 213169997. The reversal of 213169991 is 199961312.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213169991 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213169997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106584995 + 106584996.

It is an arithmetic number, because the mean of its divisors is an integer number (106584996).

Almost surely, 2^213169991 is an apocalyptic number.

213169991 is a deficient number, since it is larger than the sum of its proper divisors (1).

213169991 is an equidigital number, since it uses as much as digits as its factorization.

213169991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26244, while the sum is 41.

The square root of 213169991 is about 14600.3421535250. The cubic root of 213169991 is about 597.3680932887.

The spelling of 213169991 in words is "two hundred thirteen million, one hundred sixty-nine thousand, nine hundred ninety-one".