61644520 has 64 divisors (see below), whose sum is σ = 159770880. Its totient is φ = 20967936.

The previous prime is 61644497. The next prime is 61644547. The reversal of 61644520 is 2544616.

It is a Harshad number since it is a multiple of its sum of digits (28).

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, 37557 + ... + 39163.

It is an arithmetic number, because the mean of its divisors is an integer number (2496420).

Almost surely, 2^61644520 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 61644520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (79885440).

61644520 is an abundant number, since it is smaller than the sum of its proper divisors (98126360).

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

61644520 is a wasteful number, since it uses less digits than its factorization.

61644520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1762 (or 1758 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 61644520 is about 7851.4024224975. The cubic root of 61644520 is about 395.0312852430.

The spelling of 61644520 in words is "sixty-one million, six hundred forty-four thousand, five hundred twenty".