61506614991 has 16 divisors (see below), whose sum is σ = 82408725504. Its totient is φ = 40804601664.

The previous prime is 61506614969. The next prime is 61506614999. The reversal of 61506614991 is 19941660516.

It is not a de Polignac number, because 61506614991 - 2²¹ = 61504517839 is a prime.

It is a super-2 number, since 2×61506614991² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 61506614991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61506614999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1841260 + ... + 1874366.

It is an arithmetic number, because the mean of its divisors is an integer number (5150545344).

Almost surely, 2^61506614991 is an apocalyptic number.

61506614991 is a deficient number, since it is larger than the sum of its proper divisors (20902110513).

61506614991 is a wasteful number, since it uses less digits than its factorization.

61506614991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36110.

The product of its (nonzero) digits is 349920, while the sum is 48.

The spelling of 61506614991 in words is "sixty-one billion, five hundred six million, six hundred fourteen thousand, nine hundred ninety-one".