66743775 has 72 divisors (see below), whose sum is σ = 141133824. Its totient is φ = 29505600.

The previous prime is 66743771. The next prime is 66743779. The reversal of 66743775 is 57734766.

It is an interprime number because it is at equal distance from previous prime (66743771) and next prime (66743779).

It is not a de Polignac number, because 66743775 - 2² = 66743771 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 66743775.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66743771) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 48142 + ... + 49508.

It is an arithmetic number, because the mean of its divisors is an integer number (1960192).

Almost surely, 2^66743775 is an apocalyptic number.

66743775 is an abundant number, since it is smaller than the sum of its proper divisors (74390049).

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

66743775 is a wasteful number, since it uses less digits than its factorization.

66743775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1421 (or 1413 counting only the distinct ones).

The product of its digits is 740880, while the sum is 45.

The square root of 66743775 is about 8169.6863464885. The cubic root of 66743775 is about 405.6364022917.

Subtracting from 66743775 its reverse (57734766), we obtain a palindrome (9009009).

The spelling of 66743775 in words is "sixty-six million, seven hundred forty-three thousand, seven hundred seventy-five".