51551864 has 64 divisors (see below), whose sum is σ = 125260800. Its totient is φ = 19315584.

The previous prime is 51551861. The next prime is 51551873. The reversal of 51551864 is 46815515.

51551864 = 212² + 213² + ... + 547².

It is a happy number.

51551864 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51551861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11969 + ... + 15695.

It is an arithmetic number, because the mean of its divisors is an integer number (1957200).

Almost surely, 2^51551864 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 51551864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (62630400).

51551864 is an abundant number, since it is smaller than the sum of its proper divisors (73708936).

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

51551864 is a wasteful number, since it uses less digits than its factorization.

51551864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3772 (or 3768 counting only the distinct ones).

The product of its digits is 24000, while the sum is 35.

The square root of 51551864 is about 7179.9626739977. The cubic root of 51551864 is about 372.1757946631.

The spelling of 51551864 in words is "fifty-one million, five hundred fifty-one thousand, eight hundred sixty-four".