65505561 has 8 divisors (see below), whose sum is σ = 95280864. Its totient is φ = 39700320.

The previous prime is 65505553. The next prime is 65505571. The reversal of 65505561 is 16550556.

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

It is not a de Polignac number, because 65505561 - 2³ = 65505553 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 1985017 = 65505561 / (6 + 5 + 5 + 0 + 5 + 5 + 6 + 1).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (65505571) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 992476 + ... + 992541.

It is an arithmetic number, because the mean of its divisors is an integer number (11910108).

Almost surely, 2^65505561 is an apocalyptic number.

It is an amenable number.

65505561 is a deficient number, since it is larger than the sum of its proper divisors (29775303).

65505561 is a wasteful number, since it uses less digits than its factorization.

65505561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1985031.

The product of its (nonzero) digits is 22500, while the sum is 33.

The square root of 65505561 is about 8093.5505805549. The cubic root of 65505561 is about 403.1123064809.

It can be divided in two parts, 65505 and 561, that added together give a palindrome (66066).

The spelling of 65505561 in words is "sixty-five million, five hundred five thousand, five hundred sixty-one".