61581912 has 64 divisors (see below), whose sum is σ = 180721920. Its totient is φ = 17117568.

The previous prime is 61581893. The next prime is 61581913. The reversal of 61581912 is 21918516.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61581913) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1263 + ... + 11169.

It is an arithmetic number, because the mean of its divisors is an integer number (2823780).

Almost surely, 2^61581912 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 61581912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90360960).

61581912 is an abundant number, since it is smaller than the sum of its proper divisors (119140008).

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

61581912 is a wasteful number, since it uses less digits than its factorization.

61581912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9960 (or 9956 counting only the distinct ones).

The product of its digits is 4320, while the sum is 33.

The square root of 61581912 is about 7847.4143512370. The cubic root of 61581912 is about 394.8975047852.

The spelling of 61581912 in words is "sixty-one million, five hundred eighty-one thousand, nine hundred twelve".