61531728 has 120 divisors (see below), whose sum is σ = 173479968. Its totient is φ = 18779904.

The previous prime is 61531727. The next prime is 61531759. The reversal of 61531728 is 82713516.

61531728 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

Its product of digits (10080) is a multiple of the sum of its prime divisors (144).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61531727) 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, 918351 + ... + 918417.

Almost surely, 2^61531728 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 61531728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86739984).

61531728 is an abundant number, since it is smaller than the sum of its proper divisors (111948240).

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

61531728 is a wasteful number, since it uses less digits than its factorization.

61531728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169 (or 144 counting only the distinct ones).

The product of its digits is 10080, while the sum is 33.

The square root of 61531728 is about 7844.2162132363. The cubic root of 61531728 is about 394.7902063844.

The spelling of 61531728 in words is "sixty-one million, five hundred thirty-one thousand, seven hundred twenty-eight".