66503851 has 4 divisors (see below), whose sum is σ = 66841632. Its totient is φ = 66166072.

The previous prime is 66503849. The next prime is 66503869. The reversal of 66503851 is 15830566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15830566 = 2 ⋅7915283.

It is a cyclic number.

It is not a de Polignac number, because 66503851 - 2¹ = 66503849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66503821) 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, 168595 + ... + 168988.

It is an arithmetic number, because the mean of its divisors is an integer number (16710408).

Almost surely, 2^66503851 is an apocalyptic number.

66503851 is a deficient number, since it is larger than the sum of its proper divisors (337781).

66503851 is a wasteful number, since it uses less digits than its factorization.

66503851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337780.

The product of its (nonzero) digits is 21600, while the sum is 34.

The square root of 66503851 is about 8154.9893316914. The cubic root of 66503851 is about 405.1497713609.

It can be divided in two parts, 6650 and 3851, that added together give a palindrome (10501).

The spelling of 66503851 in words is "sixty-six million, five hundred three thousand, eight hundred fifty-one".