61643520 has 108 divisors (see below), whose sum is σ = 213320016. Its totient is φ = 16435200.

The previous prime is 61643507. The next prime is 61643539. The reversal of 61643520 is 2534616.

61643520 is a `hidden beast` number, since 616 + 43 + 5 + 2 + 0 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8845 + ... + 14195.

Almost surely, 2^61643520 is an apocalyptic number.

61643520 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61643520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106660008).

61643520 is an abundant number, since it is smaller than the sum of its proper divisors (151676496).

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

61643520 is a wasteful number, since it uses less digits than its factorization.

61643520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5378 (or 5361 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 61643520 is about 7851.3387393489. The cubic root of 61643520 is about 395.0291491601.

The spelling of 61643520 in words is "sixty-one million, six hundred forty-three thousand, five hundred twenty".