66875391 has 24 divisors (see below), whose sum is σ = 108233424. Its totient is φ = 39432960.

The previous prime is 66875357. The next prime is 66875411. The reversal of 66875391 is 19357866.

It is a happy number.

It is not a de Polignac number, because 66875391 - 2¹⁸ = 66613247 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66875311) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5466 + ... + 12791.

It is an arithmetic number, because the mean of its divisors is an integer number (4509726).

Almost surely, 2^66875391 is an apocalyptic number.

66875391 is a deficient number, since it is larger than the sum of its proper divisors (41358033).

66875391 is a wasteful number, since it uses less digits than its factorization.

66875391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18311 (or 18308 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The square root of 66875391 is about 8177.7375233007. The cubic root of 66875391 is about 405.9028600299.

The spelling of 66875391 in words is "sixty-six million, eight hundred seventy-five thousand, three hundred ninety-one".