66457728 has 48 divisors (see below), whose sum is σ = 191242350. Its totient is φ = 22152192.

The previous prime is 66457693. The next prime is 66457751. The reversal of 66457728 is 82775466.

It can be written as a sum of positive squares in only one way, i.e., 63872064 + 2585664 = 7992^2 + 1608^2 .

It is a tau number, because it is divible by the number of its divisors (48).

It is a super-2 number, since 2×66457728² = 8833259221843968, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 27693 + ... + 29996.

Almost surely, 2^66457728 is an apocalyptic number.

It is an amenable number.

66457728 is an abundant number, since it is smaller than the sum of its proper divisors (124784622).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66457728 is a wasteful number, since it uses less digits than its factorization.

66457728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57709 (or 57694 counting only the distinct ones).

The product of its digits is 564480, while the sum is 45.

The square root of 66457728 is about 8152.1609405114. The cubic root of 66457728 is about 405.0560873397.

The spelling of 66457728 in words is "sixty-six million, four hundred fifty-seven thousand, seven hundred twenty-eight".