66425815 has 4 divisors (see below), whose sum is σ = 79710984. Its totient is φ = 53140648.

The previous prime is 66425797. The next prime is 66425819. The reversal of 66425815 is 51852466.

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 66425815 - 2⁷ = 66425687 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 (66425819) 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, 6642577 + ... + 6642586.

It is an arithmetic number, because the mean of its divisors is an integer number (19927746).

Almost surely, 2^66425815 is an apocalyptic number.

66425815 is a deficient number, since it is larger than the sum of its proper divisors (13285169).

66425815 is a wasteful number, since it uses less digits than its factorization.

66425815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13285168.

The product of its digits is 57600, while the sum is 37.

The square root of 66425815 is about 8150.2033716957. The cubic root of 66425815 is about 404.9912409832.

The spelling of 66425815 in words is "sixty-six million, four hundred twenty-five thousand, eight hundred fifteen".