51693840 has 240 divisors, whose sum is σ = 194291136. Its totient is φ = 12211200.

The previous prime is 51693839. The next prime is 51693841. The reversal of 51693840 is 4839615.

It is an interprime number because it is at equal distance from previous prime (51693839) and next prime (51693841).

It is a tau number, because it is divible by the number of its divisors (240).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 51693795 and 51693804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51693841) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 483067 + ... + 483173.

Almost surely, 2^51693840 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 51693840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97145568).

51693840 is an abundant number, since it is smaller than the sum of its proper divisors (142597296).

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

51693840 is a wasteful number, since it uses less digits than its factorization.

51693840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 51693840 is about 7189.8428355563. The cubic root of 51693840 is about 372.5171440843.

It can be divided in two parts, 5169 and 3840, that added together give a palindrome (9009).

The spelling of 51693840 in words is "fifty-one million, six hundred ninety-three thousand, eight hundred forty".