61565520 has 80 divisors (see below), whose sum is σ = 193594752. Its totient is φ = 16181760.

The previous prime is 61565507. The next prime is 61565527. The reversal of 61565520 is 2556516.

61565520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61565527) 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 15 ways as a sum of consecutive naturals, for example, 15234 + ... + 18846.

Almost surely, 2^61565520 is an apocalyptic number.

61565520 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 61565520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96797376).

61565520 is an abundant number, since it is smaller than the sum of its proper divisors (132029232).

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

61565520 is a wasteful number, since it uses less digits than its factorization.

61565520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3700 (or 3694 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 30.

The square root of 61565520 is about 7846.3698612798. The cubic root of 61565520 is about 394.8624634659.

The spelling of 61565520 in words is "sixty-one million, five hundred sixty-five thousand, five hundred twenty".