66103021 has 4 divisors (see below), whose sum is σ = 69991452. Its totient is φ = 62214592.

The previous prime is 66103019. The next prime is 66103039. The reversal of 66103021 is 12030166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12030166 = 2 ⋅6015083.

It can be written as a sum of positive squares in 2 ways, for example, as 57547396 + 8555625 = 7586^2 + 2925^2 .

It is a cyclic number.

It is not a de Polignac number, because 66103021 - 2¹ = 66103019 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66103021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66103061) 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, 1944190 + ... + 1944223.

It is an arithmetic number, because the mean of its divisors is an integer number (17497863).

Almost surely, 2^66103021 is an apocalyptic number.

It is an amenable number.

66103021 is a deficient number, since it is larger than the sum of its proper divisors (3888431).

66103021 is a wasteful number, since it uses less digits than its factorization.

66103021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3888430.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 66103021 is about 8130.3764365495. The cubic root of 66103021 is about 404.3341617363.

Adding to 66103021 its reverse (12030166), we get a palindrome (78133187).

The spelling of 66103021 in words is "sixty-six million, one hundred three thousand, twenty-one".