66811487 has 4 divisors (see below), whose sum is σ = 68233056. Its totient is φ = 65389920.

The previous prime is 66811471. The next prime is 66811517. The reversal of 66811487 is 78411866.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66811487 - 2⁴ = 66811471 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66811457) 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, 710714 + ... + 710807.

It is an arithmetic number, because the mean of its divisors is an integer number (17058264).

Almost surely, 2^66811487 is an apocalyptic number.

66811487 is a deficient number, since it is larger than the sum of its proper divisors (1421569).

66811487 is a wasteful number, since it uses less digits than its factorization.

66811487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1421568.

The product of its digits is 64512, while the sum is 41.

The square root of 66811487 is about 8173.8293963111. The cubic root of 66811487 is about 405.7735295319.

The spelling of 66811487 in words is "sixty-six million, eight hundred eleven thousand, four hundred eighty-seven".