66521572 has 24 divisors (see below), whose sum is σ = 127738296. Its totient is φ = 30121728.

The previous prime is 66521551. The next prime is 66521573. The reversal of 66521572 is 27512566.

It can be written as a sum of positive squares in 4 ways, for example, as 10929636 + 55591936 = 3306^2 + 7456^2 .

It is not an unprimeable number, because it can be changed into a prime (66521573) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9313 + ... + 14824.

It is an arithmetic number, because the mean of its divisors is an integer number (5322429).

Almost surely, 2^66521572 is an apocalyptic number.

It is an amenable number.

66521572 is a deficient number, since it is larger than the sum of its proper divisors (61216724).

66521572 is a wasteful number, since it uses less digits than its factorization.

66521572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24207 (or 24205 counting only the distinct ones).

The product of its digits is 25200, while the sum is 34.

The square root of 66521572 is about 8156.0757720855. The cubic root of 66521572 is about 405.1857543472.

The spelling of 66521572 in words is "sixty-six million, five hundred twenty-one thousand, five hundred seventy-two".