66410621 has 4 divisors (see below), whose sum is σ = 66427452. Its totient is φ = 66393792.

The previous prime is 66410593. The next prime is 66410627. The reversal of 66410621 is 12601466.

It is a happy number.

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 10982596 + 55428025 = 3314^2 + 7445^2 .

It is a cyclic number.

It is not a de Polignac number, because 66410621 - 2¹⁰ = 66409597 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 (66410627) 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, 1061 + ... + 11573.

It is an arithmetic number, because the mean of its divisors is an integer number (16606863).

Almost surely, 2^66410621 is an apocalyptic number.

It is an amenable number.

66410621 is a deficient number, since it is larger than the sum of its proper divisors (16831).

66410621 is a wasteful number, since it uses less digits than its factorization.

66410621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16830.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 66410621 is about 8149.2711944075. The cubic root of 66410621 is about 404.9603598860.

The spelling of 66410621 in words is "sixty-six million, four hundred ten thousand, six hundred twenty-one".