66139841 has 4 divisors (see below), whose sum is σ = 66278400. Its totient is φ = 66001284.

The previous prime is 66139823. The next prime is 66139859. The reversal of 66139841 is 14893166.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (66139823) and next prime (66139859).

It is a cyclic number.

It is not a de Polignac number, because 66139841 - 2¹⁰ = 66138817 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 66139795 and 66139804.

It is not an unprimeable number, because it can be changed into a prime (66136841) 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, 68561 + ... + 69518.

It is an arithmetic number, because the mean of its divisors is an integer number (16569600).

Almost surely, 2^66139841 is an apocalyptic number.

It is an amenable number.

66139841 is a deficient number, since it is larger than the sum of its proper divisors (138559).

66139841 is a wasteful number, since it uses less digits than its factorization.

66139841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138558.

The product of its digits is 31104, while the sum is 38.

The square root of 66139841 is about 8132.6404691219. The cubic root of 66139841 is about 404.4092204365.

The spelling of 66139841 in words is "sixty-six million, one hundred thirty-nine thousand, eight hundred forty-one".