61515728 has 40 divisors (see below), whose sum is σ = 124043400. Its totient is φ = 29517824.

The previous prime is 61515721. The next prime is 61515733. The reversal of 61515728 is 82751516.

It can be written as a sum of positive squares in 4 ways, for example, as 238144 + 61277584 = 488^2 + 7828^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61515721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 107828 + ... + 108396.

It is an arithmetic number, because the mean of its divisors is an integer number (3101085).

Almost surely, 2^61515728 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 61515728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (62021700).

61515728 is an abundant number, since it is smaller than the sum of its proper divisors (62527672).

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

61515728 is a wasteful number, since it uses less digits than its factorization.

61515728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 839 (or 833 counting only the distinct ones).

The product of its digits is 16800, while the sum is 35.

The square root of 61515728 is about 7843.1962872288. The cubic root of 61515728 is about 394.7559845226.

The spelling of 61515728 in words is "sixty-one million, five hundred fifteen thousand, seven hundred twenty-eight".