213621973 has 2 divisors, whose sum is σ = 213621974. Its totient is φ = 213621972.

The previous prime is 213621971. The next prime is 213622007. The reversal of 213621973 is 379126312.

It is an a-pointer prime, because the next prime (213622007) can be obtained adding 213621973 to its sum of digits (34).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 145757329 + 67864644 = 12073^2 + 8238^2 .

It is a cyclic number.

It is not a de Polignac number, because 213621973 - 2¹ = 213621971 is a prime.

Together with 213621971, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213621971) 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 as a sum of consecutive naturals, namely, 106810986 + 106810987.

It is an arithmetic number, because the mean of its divisors is an integer number (106810987).

Almost surely, 2^213621973 is an apocalyptic number.

It is an amenable number.

213621973 is a deficient number, since it is larger than the sum of its proper divisors (1).

213621973 is an equidigital number, since it uses as much as digits as its factorization.

213621973 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13608, while the sum is 34.

The square root of 213621973 is about 14615.8124303783. The cubic root of 213621973 is about 597.7899929238.

The spelling of 213621973 in words is "two hundred thirteen million, six hundred twenty-one thousand, nine hundred seventy-three".