66956405 has 8 divisors (see below), whose sum is σ = 80508600. Its totient is φ = 53457856.

The previous prime is 66956359. The next prime is 66956429. The reversal of 66956405 is 50465966.

It can be written as a sum of positive squares in 4 ways, for example, as 3865156 + 63091249 = 1966^2 + 7943^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66956405 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10610 + ... + 15699.

It is an arithmetic number, because the mean of its divisors is an integer number (10063575).

Almost surely, 2^66956405 is an apocalyptic number.

It is an amenable number.

66956405 is a deficient number, since it is larger than the sum of its proper divisors (13552195).

66956405 is a wasteful number, since it uses less digits than its factorization.

66956405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26823.

The product of its (nonzero) digits is 194400, while the sum is 41.

The square root of 66956405 is about 8182.6893500853. The cubic root of 66956405 is about 406.0666997925.

The spelling of 66956405 in words is "sixty-six million, nine hundred fifty-six thousand, four hundred five".