61681144 has 64 divisors (see below), whose sum is σ = 144000000. Its totient is φ = 24167808.

The previous prime is 61681079. The next prime is 61681153. The reversal of 61681144 is 44118616.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29857 + ... + 31855.

It is an arithmetic number, because the mean of its divisors is an integer number (2250000).

Almost surely, 2^61681144 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 61681144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72000000).

61681144 is an abundant number, since it is smaller than the sum of its proper divisors (82318856).

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

61681144 is a wasteful number, since it uses less digits than its factorization.

61681144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2060 (or 2056 counting only the distinct ones).

The product of its digits is 4608, while the sum is 31.

The square root of 61681144 is about 7853.7343983611. The cubic root of 61681144 is about 395.1095012336.

The spelling of 61681144 in words is "sixty-one million, six hundred eighty-one thousand, one hundred forty-four".