61555500 has 72 divisors (see below), whose sum is σ = 194201280. Its totient is φ = 16413600.

The previous prime is 61555499. The next prime is 61555523. The reversal of 61555500 is 555516.

61555500 is a `hidden beast` number, since 6 + 155 + 5 + 500 = 666.

61555500 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

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, 2340 + ... + 11339.

It is an arithmetic number, because the mean of its divisors is an integer number (2697240).

Almost surely, 2^61555500 is an apocalyptic number.

61555500 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61555500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97100640).

61555500 is an abundant number, since it is smaller than the sum of its proper divisors (132645780).

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

61555500 is a wasteful number, since it uses less digits than its factorization.

61555500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13704 (or 13689 counting only the distinct ones).

The product of its (nonzero) digits is 3750, while the sum is 27.

The square root of 61555500 is about 7845.7313234650. The cubic root of 61555500 is about 394.8410405625.

The spelling of 61555500 in words is "sixty-one million, five hundred fifty-five thousand, five hundred".