66106521 has 12 divisors (see below), whose sum is σ = 102832548. Its totient is φ = 40680864.

The previous prime is 66106519. The next prime is 66106559. The reversal of 66106521 is 12560166.

It is a happy number.

66106521 is a `hidden beast` number, since 6 + 6 + 1 + 0 + 652 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 24890121 + 41216400 = 4989^2 + 6420^2 .

It is not a de Polignac number, because 66106521 - 2¹ = 66106519 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (66106501) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 282390 + ... + 282623.

It is an arithmetic number, because the mean of its divisors is an integer number (8569379).

Almost surely, 2^66106521 is an apocalyptic number.

It is an amenable number.

66106521 is a deficient number, since it is larger than the sum of its proper divisors (36726027).

66106521 is a wasteful number, since it uses less digits than its factorization.

66106521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 565032 (or 565029 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 66106521 is about 8130.5916758868. The cubic root of 66106521 is about 404.3412977923.

Adding to 66106521 its reverse (12560166), we get a palindrome (78666687).

It can be divided in two parts, 6610 and 6521, that added together give a palindrome (13131).

The spelling of 66106521 in words is "sixty-six million, one hundred six thousand, five hundred twenty-one".