51909520 has 160 divisors (see below), whose sum is σ = 142490880. Its totient is φ = 17418240.

The previous prime is 51909511. The next prime is 51909521. The reversal of 51909520 is 2590915.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51909521) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 731085 + ... + 731155.

It is an arithmetic number, because the mean of its divisors is an integer number (890568).

Almost surely, 2^51909520 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 51909520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (71245440).

51909520 is an abundant number, since it is smaller than the sum of its proper divisors (90581360).

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

51909520 is a wasteful number, since it uses less digits than its factorization.

51909520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153 (or 147 counting only the distinct ones).

The product of its (nonzero) digits is 4050, while the sum is 31.

The square root of 51909520 is about 7204.8261602901. The cubic root of 51909520 is about 373.0345043514.

The spelling of 51909520 in words is "fifty-one million, nine hundred nine thousand, five hundred twenty".