66061561 has 8 divisors (see below), whose sum is σ = 66830400. Its totient is φ = 65297520.

The previous prime is 66061553. The next prime is 66061571. The reversal of 66061561 is 16516066.

66061561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66061561 - 2³ = 66061553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66061571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31380 + ... + 33418.

It is an arithmetic number, because the mean of its divisors is an integer number (8353800).

Almost surely, 2^66061561 is an apocalyptic number.

It is an amenable number.

66061561 is a deficient number, since it is larger than the sum of its proper divisors (768839).

66061561 is a wasteful number, since it uses less digits than its factorization.

66061561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2399.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 66061561 is about 8127.8263391881. The cubic root of 66061561 is about 404.2496108839.

The spelling of 66061561 in words is "sixty-six million, sixty-one thousand, five hundred sixty-one".