61544081556 has 120 divisors (see below), whose sum is σ = 161757376704. Its totient is φ = 20404275840.

The previous prime is 61544081551. The next prime is 61544081563. The reversal of 61544081556 is 65518044516.

61544081556 is a `hidden beast` number, since 6 + 1 + 54 + 40 + 8 + 1 + 556 = 666.

It is a super-2 number, since 2×61544081556² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61544081551) 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 39 ways as a sum of consecutive naturals, for example, 74779761 + ... + 74780583.

Almost surely, 2^61544081556 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 61544081556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80878688352).

61544081556 is an abundant number, since it is smaller than the sum of its proper divisors (100213295148).

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

61544081556 is a wasteful number, since it uses less digits than its factorization.

61544081556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1803 (or 1792 counting only the distinct ones).

The product of its (nonzero) digits is 576000, while the sum is 45.

The spelling of 61544081556 in words is "sixty-one billion, five hundred forty-four million, eighty-one thousand, five hundred fifty-six".