61561565515501 has 12 divisors (see below), whose sum is σ = 62901012763260. Its totient is φ = 60250060798400.

The previous prime is 61561565515493. The next prime is 61561565515531. The reversal of 61561565515501 is 10551556516516.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 22393669518025 + 39167895997476 = 4732195^2 + 6258426^2 .

It is not a de Polignac number, because 61561565515501 - 2³ = 61561565515493 is a prime.

It is a super-3 number, since 3×61561565515501³ (a number of 42 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61561565515531) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 82663401 + ... + 83404801.

It is an arithmetic number, because the mean of its divisors is an integer number (5241751063605).

Almost surely, 2^{61561565515501} is an apocalyptic number.

It is an amenable number.

61561565515501 is a deficient number, since it is larger than the sum of its proper divisors (1339447247759).

61561565515501 is an equidigital number, since it uses as much as digits as its factorization.

61561565515501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 779084 (or 779037 counting only the distinct ones).

The product of its (nonzero) digits is 3375000, while the sum is 52.

The spelling of 61561565515501 in words is "sixty-one trillion, five hundred sixty-one billion, five hundred sixty-five million, five hundred fifteen thousand, five hundred one".