66895621 has 4 divisors (see below), whose sum is σ = 72041452. Its totient is φ = 61749792.

The previous prime is 66895603. The next prime is 66895627. The reversal of 66895621 is 12659866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 24502500 + 42393121 = 4950^2 + 6511^2 .

It is not a de Polignac number, because 66895621 - 2¹⁷ = 66764549 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 (66895627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2572896 + ... + 2572921.

It is an arithmetic number, because the mean of its divisors is an integer number (18010363).

Almost surely, 2^66895621 is an apocalyptic number.

It is an amenable number.

66895621 is a deficient number, since it is larger than the sum of its proper divisors (5145831).

66895621 is a wasteful number, since it uses less digits than its factorization.

66895621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5145830.

The product of its digits is 155520, while the sum is 43.

The square root of 66895621 is about 8178.9743244492. The cubic root of 66895621 is about 405.9437848349.

The spelling of 66895621 in words is "sixty-six million, eight hundred ninety-five thousand, six hundred twenty-one".