66434581 has 4 divisors (see below), whose sum is σ = 68577664. Its totient is φ = 64291500.

The previous prime is 66434579. The next prime is 66434609. The reversal of 66434581 is 18543466.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18543466 = 2 ⋅9271733.

It is a cyclic number.

It is not a de Polignac number, because 66434581 - 2¹ = 66434579 is a prime.

It is a super-2 number, since 2×66434581² = 8827107105291122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66434581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66434561) 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, 1071495 + ... + 1071556.

It is an arithmetic number, because the mean of its divisors is an integer number (17144416).

Almost surely, 2^66434581 is an apocalyptic number.

It is an amenable number.

66434581 is a deficient number, since it is larger than the sum of its proper divisors (2143083).

66434581 is a wasteful number, since it uses less digits than its factorization.

66434581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2143082.

The product of its digits is 69120, while the sum is 37.

The square root of 66434581 is about 8150.7411319462. The cubic root of 66434581 is about 405.0090553277.

It can be divided in two parts, 664 and 34581, that added together give a triangular number (35245 = T₂₆₅).

The spelling of 66434581 in words is "sixty-six million, four hundred thirty-four thousand, five hundred eighty-one".