61211611217 has 4 divisors (see below), whose sum is σ = 61292472756. Its totient is φ = 61130749680.

The previous prime is 61211611183. The next prime is 61211611243. The reversal of 61211611217 is 71211611216.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27226320016 + 33985291201 = 165004^2 + 184351^2 .

It is a cyclic number.

It is not a de Polignac number, because 61211611217 - 2¹⁰ = 61211610193 is a prime.

It is a super-2 number, since 2×61211611217² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 61211611217.

It is not an unprimeable number, because it can be changed into a prime (61211611277) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40429634 + ... + 40431147.

It is an arithmetic number, because the mean of its divisors is an integer number (15323118189).

Almost surely, 2^61211611217 is an apocalyptic number.

It is an amenable number.

61211611217 is a deficient number, since it is larger than the sum of its proper divisors (80861539).

61211611217 is an equidigital number, since it uses as much as digits as its factorization.

61211611217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80861538.

The product of its digits is 1008, while the sum is 29.

Subtracting 61211611217 from its reverse (71211611216), we obtain a palindrome (9999999999).

The spelling of 61211611217 in words is "sixty-one billion, two hundred eleven million, six hundred eleven thousand, two hundred seventeen".