51720552 has 128 divisors (see below), whose sum is σ = 157046400. Its totient is φ = 15676416.

The previous prime is 51720517. The next prime is 51720563. The reversal of 51720552 is 25502715.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

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 31 ways as a sum of consecutive naturals, for example, 317223 + ... + 317385.

It is an arithmetic number, because the mean of its divisors is an integer number (1226925).

Almost surely, 2^51720552 is an apocalyptic number.

51720552 is a gapful number since it is divisible by the number (52) 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 51720552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78523200).

51720552 is an abundant number, since it is smaller than the sum of its proper divisors (105325848).

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

51720552 is a wasteful number, since it uses less digits than its factorization.

51720552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304 (or 294 counting only the distinct ones).

The product of its (nonzero) digits is 3500, while the sum is 27.

The square root of 51720552 is about 7191.7002162215. The cubic root of 51720552 is about 372.5812972116.

The spelling of 51720552 in words is "fifty-one million, seven hundred twenty thousand, five hundred fifty-two".