66828421 has 6 divisors (see below), whose sum is σ = 73456166. Its totient is φ = 60753000.

The previous prime is 66828371. The next prime is 66828431. The reversal of 66828421 is 12482866.

It can be written as a sum of positive squares in only one way, i.e., 33477796 + 33350625 = 5786^2 + 5775^2 .

It is not a de Polignac number, because 66828421 - 2¹¹ = 66826373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66828431) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 276030 + ... + 276271.

Almost surely, 2^66828421 is an apocalyptic number.

It is an amenable number.

66828421 is a deficient number, since it is larger than the sum of its proper divisors (6627745).

66828421 is a wasteful number, since it uses less digits than its factorization.

66828421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 552323 (or 552312 counting only the distinct ones).

The product of its digits is 36864, while the sum is 37.

The square root of 66828421 is about 8174.8651976653. The cubic root of 66828421 is about 405.8078090089.

The spelling of 66828421 in words is "sixty-six million, eight hundred twenty-eight thousand, four hundred twenty-one".