75666639 has 4 divisors (see below), whose sum is σ = 100888856. Its totient is φ = 50444424.

The previous prime is 75666631. The next prime is 75666649. The reversal of 75666639 is 93666657.

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

It is not a de Polignac number, because 75666639 - 2³ = 75666631 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (75666631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12611104 + ... + 12611109.

It is an arithmetic number, because the mean of its divisors is an integer number (25222214).

Almost surely, 2^75666639 is an apocalyptic number.

75666639 is a deficient number, since it is larger than the sum of its proper divisors (25222217).

75666639 is a wasteful number, since it uses less digits than its factorization.

75666639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25222216.

The product of its digits is 1224720, while the sum is 48.

The square root of 75666639 is about 8698.6573101830. The cubic root of 75666639 is about 422.9621268396.

The spelling of 75666639 in words is "seventy-five million, six hundred sixty-six thousand, six hundred thirty-nine".