66821145 has 16 divisors (see below), whose sum is σ = 107110080. Its totient is φ = 35572544.

The previous prime is 66821143. The next prime is 66821171. The reversal of 66821145 is 54112866.

It is a cyclic number.

It is not a de Polignac number, because 66821145 - 2¹ = 66821143 is a prime.

It is a super-2 number, since 2×66821145² = 8930130838222050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66821143) 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, 5011 + ... + 12599.

It is an arithmetic number, because the mean of its divisors is an integer number (6694380).

Almost surely, 2^66821145 is an apocalyptic number.

It is an amenable number.

66821145 is a deficient number, since it is larger than the sum of its proper divisors (40288935).

66821145 is a wasteful number, since it uses less digits than its factorization.

66821145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8184.

The product of its digits is 11520, while the sum is 33.

The square root of 66821145 is about 8174.4201629229. The cubic root of 66821145 is about 405.7930809200.

It can be divided in two parts, 66821 and 145, that added together give a palindrome (66966).

The spelling of 66821145 in words is "sixty-six million, eight hundred twenty-one thousand, one hundred forty-five".