66611538 has 32 divisors (see below), whose sum is σ = 169173120. Its totient is φ = 19031760.

The previous prime is 66611537. The next prime is 66611539. The reversal of 66611538 is 83511666.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (66611537) and next prime (66611539).

It is not an unprimeable number, because it can be changed into a prime (66611533) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87733 + ... + 88488.

It is an arithmetic number, because the mean of its divisors is an integer number (5286660).

Almost surely, 2^66611538 is an apocalyptic number.

66611538 is an abundant number, since it is smaller than the sum of its proper divisors (102561582).

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

66611538 is a wasteful number, since it uses less digits than its factorization.

66611538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176239 (or 176233 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 66611538 is about 8161.5891834863. The cubic root of 66611538 is about 405.3683343205.

The spelling of 66611538 in words is "sixty-six million, six hundred eleven thousand, five hundred thirty-eight".