65561918687 has 16 divisors (see below), whose sum is σ = 66445288800. Its totient is φ = 64685716992.

The previous prime is 65561918663. The next prime is 65561918689. The reversal of 65561918687 is 78681916556.

It is a cyclic number.

It is not a de Polignac number, because 65561918687 - 2⁸ = 65561918431 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 (65561918689) 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, 15992564 + ... + 15996662.

It is an arithmetic number, because the mean of its divisors is an integer number (4152830550).

Almost surely, 2^65561918687 is an apocalyptic number.

65561918687 is a deficient number, since it is larger than the sum of its proper divisors (883370113).

65561918687 is a wasteful number, since it uses less digits than its factorization.

65561918687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4922.

The product of its digits is 21772800, while the sum is 62.

The spelling of 65561918687 in words is "sixty-five billion, five hundred sixty-one million, nine hundred eighteen thousand, six hundred eighty-seven".