66581871 has 16 divisors (see below), whose sum is σ = 93744000. Its totient is φ = 41918688.

The previous prime is 66581861. The next prime is 66581881. The reversal of 66581871 is 17818566.

It is an interprime number because it is at equal distance from previous prime (66581861) and next prime (66581881).

It is not a de Polignac number, because 66581871 - 2⁶ = 66581807 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66581821) 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, 18220 + ... + 21566.

It is an arithmetic number, because the mean of its divisors is an integer number (5859000).

Almost surely, 2^66581871 is an apocalyptic number.

66581871 is a deficient number, since it is larger than the sum of its proper divisors (27162129).

66581871 is a wasteful number, since it uses less digits than its factorization.

66581871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3718.

The product of its digits is 80640, while the sum is 42.

The square root of 66581871 is about 8159.7715041538. The cubic root of 66581871 is about 405.3081453075.

The spelling of 66581871 in words is "sixty-six million, five hundred eighty-one thousand, eight hundred seventy-one".