66139745 has 8 divisors (see below), whose sum is σ = 90705984. Its totient is φ = 45352944.

The previous prime is 66139739. The next prime is 66139747. The reversal of 66139745 is 54793166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66139745 - 2⁴ = 66139729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66139747) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 944819 + ... + 944888.

It is an arithmetic number, because the mean of its divisors is an integer number (11338248).

Almost surely, 2^66139745 is an apocalyptic number.

It is an amenable number.

66139745 is a deficient number, since it is larger than the sum of its proper divisors (24566239).

66139745 is a wasteful number, since it uses less digits than its factorization.

66139745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1889719.

The product of its digits is 136080, while the sum is 41.

The square root of 66139745 is about 8132.6345669777. The cubic root of 66139745 is about 404.4090247738.

The spelling of 66139745 in words is "sixty-six million, one hundred thirty-nine thousand, seven hundred forty-five".