66728426 has 4 divisors (see below), whose sum is σ = 100092642. Its totient is φ = 33364212.

The previous prime is 66728423. The next prime is 66728477. The reversal of 66728426 is 62482766.

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

It can be written as a sum of positive squares in only one way, i.e., 40972801 + 25755625 = 6401^2 + 5075^2 .

It is not an unprimeable number, because it can be changed into a prime (66728423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16682105 + ... + 16682108.

Almost surely, 2^66728426 is an apocalyptic number.

66728426 is a deficient number, since it is larger than the sum of its proper divisors (33364216).

66728426 is a wasteful number, since it uses less digits than its factorization.

66728426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33364215.

The product of its digits is 193536, while the sum is 41.

The square root of 66728426 is about 8168.7469051257. The cubic root of 66728426 is about 405.6053053069.

The spelling of 66728426 in words is "sixty-six million, seven hundred twenty-eight thousand, four hundred twenty-six".