66810642 has 24 divisors (see below), whose sum is σ = 138082608. Its totient is φ = 21549960.

The previous prime is 66810599. The next prime is 66810649. The reversal of 66810642 is 24601866.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (66810649) 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, 28 + ... + 11559.

It is an arithmetic number, because the mean of its divisors is an integer number (5753442).

Almost surely, 2^66810642 is an apocalyptic number.

66810642 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

66810642 is an abundant number, since it is smaller than the sum of its proper divisors (71271966).

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

66810642 is a wasteful number, since it uses less digits than its factorization.

66810642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11654 (or 11623 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 66810642 is about 8173.7777067889. Note that the first 4 decimals coincide. The cubic root of 66810642 is about 405.7718188477.

The spelling of 66810642 in words is "sixty-six million, eight hundred ten thousand, six hundred forty-two".