66891228 has 24 divisors (see below), whose sum is σ = 156444288. Its totient is φ = 22244976.

The previous prime is 66891203. The next prime is 66891233. The reversal of 66891228 is 82219866.

It is a self number, because there is not a number n which added to its sum of digits gives 66891228.

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, 976 + ... + 11607.

It is an arithmetic number, because the mean of its divisors is an integer number (6518512).

Almost surely, 2^66891228 is an apocalyptic number.

It is an amenable number.

66891228 is an abundant number, since it is smaller than the sum of its proper divisors (89553060).

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

66891228 is a wasteful number, since it uses less digits than its factorization.

66891228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13033 (or 13031 counting only the distinct ones).

The product of its digits is 82944, while the sum is 42.

The square root of 66891228 is about 8178.7057655842. The cubic root of 66891228 is about 405.9348986026.

The spelling of 66891228 in words is "sixty-six million, eight hundred ninety-one thousand, two hundred twenty-eight".