66629391 has 4 divisors (see below), whose sum is σ = 88839192. Its totient is φ = 44419592.

The previous prime is 66629389. The next prime is 66629399. The reversal of 66629391 is 19392666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66629391 - 2¹ = 66629389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66629399) 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 in 3 ways as a sum of consecutive naturals, for example, 11104896 + ... + 11104901.

It is an arithmetic number, because the mean of its divisors is an integer number (22209798).

Almost surely, 2^66629391 is an apocalyptic number.

66629391 is a deficient number, since it is larger than the sum of its proper divisors (22209801).

66629391 is a wasteful number, since it uses less digits than its factorization.

66629391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22209800.

The product of its digits is 104976, while the sum is 42.

The square root of 66629391 is about 8162.6828310305. The cubic root of 66629391 is about 405.4045462373.

The spelling of 66629391 in words is "sixty-six million, six hundred twenty-nine thousand, three hundred ninety-one".