191213551 has 2 divisors, whose sum is σ = 191213552. Its totient is φ = 191213550.

The previous prime is 191213537. The next prime is 191213593. The reversal of 191213551 is 155312191.

It is a weak prime.

It is an emirp because it is prime and its reverse (155312191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191213551 - 2⁹ = 191213039 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 (191213051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95606775 + 95606776.

It is an arithmetic number, because the mean of its divisors is an integer number (95606776).

Almost surely, 2^191213551 is an apocalyptic number.

191213551 is a deficient number, since it is larger than the sum of its proper divisors (1).

191213551 is an equidigital number, since it uses as much as digits as its factorization.

191213551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1350, while the sum is 28.

The square root of 191213551 is about 13827.9988067688. The cubic root of 191213551 is about 576.1110726113. Note that the first 3 decimals are identical.

The spelling of 191213551 in words is "one hundred ninety-one million, two hundred thirteen thousand, five hundred fifty-one".