66339561 has 16 divisors (see below), whose sum is σ = 89796224. Its totient is φ = 43559424.

The previous prime is 66339529. The next prime is 66339563. The reversal of 66339561 is 16593366.

It is not a de Polignac number, because 66339561 - 2⁵ = 66339529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66339563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 80196 + ... + 81018.

It is an arithmetic number, because the mean of its divisors is an integer number (5612264).

Almost surely, 2^66339561 is an apocalyptic number.

It is an amenable number.

66339561 is a deficient number, since it is larger than the sum of its proper divisors (23456663).

66339561 is a wasteful number, since it uses less digits than its factorization.

66339561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1200.

The product of its digits is 87480, while the sum is 39.

The square root of 66339561 is about 8144.9101284176. The cubic root of 66339561 is about 404.8158711855.

The spelling of 66339561 in words is "sixty-six million, three hundred thirty-nine thousand, five hundred sixty-one".