66813228 has 48 divisors (see below), whose sum is σ = 177260160. Its totient is φ = 21751632.

The previous prime is 66813221. The next prime is 66813233. The reversal of 66813228 is 82231866.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 66813192 and 66813201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66813221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2550 + ... + 11837.

It is an arithmetic number, because the mean of its divisors is an integer number (3692920).

Almost surely, 2^66813228 is an apocalyptic number.

It is an amenable number.

66813228 is an abundant number, since it is smaller than the sum of its proper divisors (110446932).

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

66813228 is a wasteful number, since it uses less digits than its factorization.

66813228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14443 (or 14435 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 66813228 is about 8173.9358940476. The cubic root of 66813228 is about 405.7770541034. Note that the first 3 decimals are identical.

The spelling of 66813228 in words is "sixty-six million, eight hundred thirteen thousand, two hundred twenty-eight".