66864525 has 96 divisors (see below), whose sum is σ = 138824448. Its totient is φ = 27648000.

The previous prime is 66864521. The next prime is 66864533. The reversal of 66864525 is 52546866.

It is not a de Polignac number, because 66864525 - 2² = 66864521 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66864521) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 661975 + ... + 662075.

It is an arithmetic number, because the mean of its divisors is an integer number (1446088).

Almost surely, 2^66864525 is an apocalyptic number.

66864525 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

66864525 is an abundant number, since it is smaller than the sum of its proper divisors (71959923).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66864525 is a wasteful number, since it uses less digits than its factorization.

66864525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231 (or 226 counting only the distinct ones).

The product of its digits is 345600, while the sum is 42.

The square root of 66864525 is about 8177.0731316285. The cubic root of 66864525 is about 405.8808749653.

It can be divided in two parts, 6686 and 4525, that added together give a palindrome (11211).

The spelling of 66864525 in words is "sixty-six million, eight hundred sixty-four thousand, five hundred twenty-five".