66133391 has 2 divisors, whose sum is σ = 66133392. Its totient is φ = 66133390.

The previous prime is 66133351. The next prime is 66133399. The reversal of 66133391 is 19333166.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66133391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66133399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33066695 + 33066696.

It is an arithmetic number, because the mean of its divisors is an integer number (33066696).

Almost surely, 2^66133391 is an apocalyptic number.

66133391 is a deficient number, since it is larger than the sum of its proper divisors (1).

66133391 is an equidigital number, since it uses as much as digits as its factorization.

66133391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8748, while the sum is 32.

The square root of 66133391 is about 8132.2439092787. The cubic root of 66133391 is about 404.3960739264.

The spelling of 66133391 in words is "sixty-six million, one hundred thirty-three thousand, three hundred ninety-one".