61000000000 has 200 divisors, whose sum is σ = 154848616956. Its totient is φ = 24000000000.

The previous prime is 60999999941. The next prime is 61000000001. The reversal of 61000000000 is 16.

It can be written as a sum of positive squares in 10 ways, for example, as 21185384704 + 39814615296 = 145552^2 + 199536^2 .

It is a tau number, because it is divible by the number of its divisors (200).

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 61000000000.

It is not an unprimeable number, because it can be changed into a prime (61000000001) 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 19 ways as a sum of consecutive naturals, for example, 999999970 + ... + 1000000030.

Almost surely, 2^61000000000 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61000000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77424308478).

61000000000 is an abundant number, since it is smaller than the sum of its proper divisors (93848616956).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61000000000 is an frugal number, since it uses more digits than its factorization.

61000000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124 (or 68 counting only the distinct ones).

The product of its (nonzero) digits is 6, while the sum is 7.

Adding to 61000000000 its reverse (16), we get a palindrome (61000000016).

The spelling of 61000000000 in words is "sixty-one billion", and thus it is an aban number and an uban number.