66521025 has 36 divisors (see below), whose sum is σ = 121190160. Its totient is φ = 34869600.

The previous prime is 66521023. The next prime is 66521029. The reversal of 66521025 is 52012566.

66521025 is a `hidden beast` number, since 6 + 652 + 1 + 0 + 2 + 5 = 666.

It is not a de Polignac number, because 66521025 - 2¹ = 66521023 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66521025.

It is not an unprimeable number, because it can be changed into a prime (66521023) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 10770 + ... + 15780.

Almost surely, 2^66521025 is an apocalyptic number.

It is an amenable number.

66521025 is a deficient number, since it is larger than the sum of its proper divisors (54669135).

66521025 is a wasteful number, since it uses less digits than its factorization.

66521025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5086 (or 5078 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 66521025 is about 8156.0422387332. The cubic root of 66521025 is about 405.1846437440.

The spelling of 66521025 in words is "sixty-six million, five hundred twenty-one thousand, twenty-five".