61533220 has 72 divisors (see below), whose sum is σ = 154470456. Its totient is φ = 20514816.

The previous prime is 61533161. The next prime is 61533247. The reversal of 61533220 is 2233516.

61533220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 34409956 + 27123264 = 5866^2 + 5208^2 .

It is a junction number, because it is equal to n+sod(n) for n = 61533191 and 61533200.

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, 35412 + ... + 37108.

It is an arithmetic number, because the mean of its divisors is an integer number (2145423).

Almost surely, 2^61533220 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 61533220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77235228).

61533220 is an abundant number, since it is smaller than the sum of its proper divisors (92937236).

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

61533220 is a wasteful number, since it uses less digits than its factorization.

61533220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1757 (or 1748 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 22.

The square root of 61533220 is about 7844.3113145770. The cubic root of 61533220 is about 394.7933972707.

Adding to 61533220 its reverse (2233516), we get a palindrome (63766736).

The spelling of 61533220 in words is "sixty-one million, five hundred thirty-three thousand, two hundred twenty".