61217309961 has 24 divisors (see below), whose sum is σ = 95910056424. Its totient is φ = 37474007040.

The previous prime is 61217309957. The next prime is 61217309987. The reversal of 61217309961 is 16990371216.

It can be written as a sum of positive squares in 4 ways, for example, as 3581304336 + 57636005625 = 59844^2 + 240075^2 .

It is not a de Polignac number, because 61217309961 - 2² = 61217309957 is a prime.

It is a super-2 number, since 2×61217309961² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (61217309911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4873156 + ... + 4885701.

It is an arithmetic number, because the mean of its divisors is an integer number (3996252351).

Almost surely, 2^61217309961 is an apocalyptic number.

It is an amenable number.

61217309961 is a deficient number, since it is larger than the sum of its proper divisors (34692746463).

61217309961 is a wasteful number, since it uses less digits than its factorization.

61217309961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9758921 (or 9758918 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 45.

The spelling of 61217309961 in words is "sixty-one billion, two hundred seventeen million, three hundred nine thousand, nine hundred sixty-one".