66426257 has 4 divisors (see below), whose sum is σ = 66442560. Its totient is φ = 66409956.

The previous prime is 66426247. The next prime is 66426263. The reversal of 66426257 is 75262466.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66426257 is a prime.

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 66426257.

It is not an unprimeable number, because it can be changed into a prime (66426247) 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, 3908 + ... + 12170.

It is an arithmetic number, because the mean of its divisors is an integer number (16610640).

Almost surely, 2^66426257 is an apocalyptic number.

It is an amenable number.

66426257 is a deficient number, since it is larger than the sum of its proper divisors (16303).

66426257 is an equidigital number, since it uses as much as digits as its factorization.

66426257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16302.

The product of its digits is 120960, while the sum is 38.

The square root of 66426257 is about 8150.2304875384. The cubic root of 66426257 is about 404.9921392571.

The spelling of 66426257 in words is "sixty-six million, four hundred twenty-six thousand, two hundred fifty-seven".