51381632 has 64 divisors (see below), whose sum is σ = 110453760. Its totient is φ = 23738880.

The previous prime is 51381623. The next prime is 51381637. The reversal of 51381632 is 23618315.

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 51381595 and 51381604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51381637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90983 + ... + 91545.

It is an arithmetic number, because the mean of its divisors is an integer number (1725840).

Almost surely, 2^51381632 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 51381632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55226880).

51381632 is an abundant number, since it is smaller than the sum of its proper divisors (59072128).

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

51381632 is a wasteful number, since it uses less digits than its factorization.

51381632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 631 (or 619 counting only the distinct ones).

The product of its digits is 4320, while the sum is 29.

The square root of 51381632 is about 7168.0982136129. The cubic root of 51381632 is about 371.7656827846.

Adding to 51381632 its reverse (23618315), we get a palindrome (74999947).

The spelling of 51381632 in words is "fifty-one million, three hundred eighty-one thousand, six hundred thirty-two".