66607531 has 4 divisors (see below), whose sum is σ = 66646672. Its totient is φ = 66568392.

The previous prime is 66607529. The next prime is 66607543. The reversal of 66607531 is 13570666.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66607531 - 2¹ = 66607529 is a prime.

It is a super-2 number, since 2×66607531² = 8873126371831922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66607501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16896 + ... + 20461.

It is an arithmetic number, because the mean of its divisors is an integer number (16661668).

Almost surely, 2^66607531 is an apocalyptic number.

66607531 is a deficient number, since it is larger than the sum of its proper divisors (39141).

66607531 is a wasteful number, since it uses less digits than its factorization.

66607531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39140.

The product of its (nonzero) digits is 22680, while the sum is 34.

The square root of 66607531 is about 8161.3437006415. The cubic root of 66607531 is about 405.3602058814.

The spelling of 66607531 in words is "sixty-six million, six hundred seven thousand, five hundred thirty-one".