61611220 has 48 divisors (see below), whose sum is σ = 143490816. Its totient is φ = 22032000.

The previous prime is 61611191. The next prime is 61611223. The reversal of 61611220 is 2211616.

61611220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61611223) 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, 11125 + ... + 15715.

It is an arithmetic number, because the mean of its divisors is an integer number (2989392).

Almost surely, 2^61611220 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 61611220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (71745408).

61611220 is an abundant number, since it is smaller than the sum of its proper divisors (81879596).

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

61611220 is a wasteful number, since it uses less digits than its factorization.

61611220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4672 (or 4670 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 61611220 is about 7849.2814957804. The cubic root of 61611220 is about 394.9601412539.

Adding to 61611220 its reverse (2211616), we get a palindrome (63822836).

It can be divided in two parts, 6161 and 1220, that added together give a triangular number (7381 = T₁₂₁).

The spelling of 61611220 in words is "sixty-one million, six hundred eleven thousand, two hundred twenty".