66398625 has 24 divisors (see below), whose sum is σ = 119696616. Its totient is φ = 35412000.

The previous prime is 66398623. The next prime is 66398627. The reversal of 66398625 is 52689366.

It is a happy number.

66398625 is a `hidden beast` number, since 6 + 639 + 8 + 6 + 2 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (66398623) and next prime (66398627).

It can be written as a sum of positive squares in 4 ways, for example, as 6305121 + 60093504 = 2511^2 + 7752^2 .

It is not a de Polignac number, because 66398625 - 2¹ = 66398623 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (66398623) 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, 28386 + ... + 30635.

It is an arithmetic number, because the mean of its divisors is an integer number (4987359).

Almost surely, 2^66398625 is an apocalyptic number.

It is an amenable number.

66398625 is a deficient number, since it is larger than the sum of its proper divisors (53297991).

66398625 is a wasteful number, since it uses less digits than its factorization.

66398625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59042 (or 59029 counting only the distinct ones).

The product of its digits is 466560, while the sum is 45.

The square root of 66398625 is about 8148.5351444293. The cubic root of 66398625 is about 404.9359752472.

The spelling of 66398625 in words is "sixty-six million, three hundred ninety-eight thousand, six hundred twenty-five".