65661551561613 has 32 divisors (see below), whose sum is σ = 100171532528640. Its totient is φ = 37477461513600.

The previous prime is 65661551561609. The next prime is 65661551561647. The reversal of 65661551561613 is 31616515516656.

It is a happy number.

It is not a de Polignac number, because 65661551561613 - 2² = 65661551561609 is a prime.

It is a super-2 number, since 2×65661551561613² (a number of 28 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65661551561663) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 122498638 + ... + 123033488.

It is an arithmetic number, because the mean of its divisors is an integer number (3130360391520).

Almost surely, 2^{65661551561613} is an apocalyptic number.

It is an amenable number.

65661551561613 is a deficient number, since it is larger than the sum of its proper divisors (34509980967027).

65661551561613 is a wasteful number, since it uses less digits than its factorization.

65661551561613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 541617.

The product of its digits is 14580000, while the sum is 57.

The spelling of 65661551561613 in words is "sixty-five trillion, six hundred sixty-one billion, five hundred fifty-one million, five hundred sixty-one thousand, six hundred thirteen".