61131520 has 72 divisors (see below), whose sum is σ = 147830256. Its totient is φ = 24219648.

The previous prime is 61131487. The next prime is 61131527. The reversal of 61131520 is 2513116.

It is not an unprimeable number, because it can be changed into a prime (61131527) 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, 208494 + ... + 208786.

It is an arithmetic number, because the mean of its divisors is an integer number (2053198).

Almost surely, 2^61131520 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 61131520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73915128).

61131520 is an abundant number, since it is smaller than the sum of its proper divisors (86698736).

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

61131520 is a wasteful number, since it uses less digits than its factorization.

61131520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 477 (or 463 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 61131520 is about 7818.6648476578. The cubic root of 61131520 is about 393.9324267634.

Adding to 61131520 its reverse (2513116), we get a palindrome (63644636).

It can be divided in two parts, 611 and 31520, that added together give a triangular number (32131 = T₂₅₃).

The spelling of 61131520 in words is "sixty-one million, one hundred thirty-one thousand, five hundred twenty".