66270821 has 4 divisors (see below), whose sum is σ = 66316992. Its totient is φ = 66224652.

The previous prime is 66270779. The next prime is 66270823. The reversal of 66270821 is 12807266.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66270821 - 2¹⁴ = 66254437 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 (66270823) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20861 + ... + 23826.

It is an arithmetic number, because the mean of its divisors is an integer number (16579248).

Almost surely, 2^66270821 is an apocalyptic number.

It is an amenable number.

66270821 is a deficient number, since it is larger than the sum of its proper divisors (46171).

66270821 is a wasteful number, since it uses less digits than its factorization.

66270821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46170.

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 66270821 is about 8140.6892214357. The cubic root of 66270821 is about 404.6760016043.

The spelling of 66270821 in words is "sixty-six million, two hundred seventy thousand, eight hundred twenty-one".