213393991 has 2 divisors, whose sum is σ = 213393992. Its totient is φ = 213393990.

The previous prime is 213393967. The next prime is 213394003. The reversal of 213393991 is 199393312.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213393991 is a prime.

It is equal to p_11778556 and since 213393991 and 11778556 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213394991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106696995 + 106696996.

It is an arithmetic number, because the mean of its divisors is an integer number (106696996).

Almost surely, 2^213393991 is an apocalyptic number.

213393991 is a deficient number, since it is larger than the sum of its proper divisors (1).

213393991 is an equidigital number, since it uses as much as digits as its factorization.

213393991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 39366, while the sum is 40.

The square root of 213393991 is about 14608.0111924930. The cubic root of 213393991 is about 597.5772590818.

The spelling of 213393991 in words is "two hundred thirteen million, three hundred ninety-three thousand, nine hundred ninety-one".