66411709 has 24 divisors (see below), whose sum is σ = 83914488. Its totient is φ = 52093440.

The previous prime is 66411701. The next prime is 66411721. The reversal of 66411709 is 90711466.

It can be written as a sum of positive squares in 4 ways, for example, as 1044484 + 65367225 = 1022^2 + 8085^2 .

It is not a de Polignac number, because 66411709 - 2³ = 66411701 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66411701) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 86889 + ... + 87649.

It is an arithmetic number, because the mean of its divisors is an integer number (3496437).

Almost surely, 2^66411709 is an apocalyptic number.

It is an amenable number.

66411709 is a deficient number, since it is larger than the sum of its proper divisors (17502779).

66411709 is a wasteful number, since it uses less digits than its factorization.

66411709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 925 (or 918 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 66411709 is about 8149.3379485698. The cubic root of 66411709 is about 404.9625713518.

The spelling of 66411709 in words is "sixty-six million, four hundred eleven thousand, seven hundred nine".