66865638 has 32 divisors (see below), whose sum is σ = 155347200. Its totient is φ = 18790560.

The previous prime is 66865637. The next prime is 66865639. The reversal of 66865638 is 83656866.

It is an interprime number because it is at equal distance from previous prime (66865637) and next prime (66865639).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66865633) 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, 10488 + ... + 15611.

It is an arithmetic number, because the mean of its divisors is an integer number (4854600).

Almost surely, 2^66865638 is an apocalyptic number.

66865638 is an abundant number, since it is smaller than the sum of its proper divisors (88481562).

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

66865638 is a wasteful number, since it uses less digits than its factorization.

66865638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26172.

The product of its digits is 1244160, while the sum is 48.

The square root of 66865638 is about 8177.1411874811. The cubic root of 66865638 is about 405.8831269961.

The spelling of 66865638 in words is "sixty-six million, eight hundred sixty-five thousand, six hundred thirty-eight".