51993942 has 96 divisors (see below), whose sum is σ = 140856576. Its totient is φ = 12450240.

The previous prime is 51993941. The next prime is 51993959. The reversal of 51993942 is 24939915.

It is a Smith number, since the sum of its digits (42) 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 (42).

It is a junction number, because it is equal to n+sod(n) for n = 51993894 and 51993903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51993941) 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, 65673 + ... + 66459.

It is an arithmetic number, because the mean of its divisors is an integer number (1467256).

Almost surely, 2^51993942 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51993942, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (70428288).

51993942 is an abundant number, since it is smaller than the sum of its proper divisors (88862634).

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

51993942 is a wasteful number, since it uses less digits than its factorization.

51993942 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 834 (or 823 counting only the distinct ones).

The product of its digits is 87480, while the sum is 42.

The square root of 51993942 is about 7210.6824919698. The cubic root of 51993942 is about 373.2366205338.

51993942 divided by its sum of digits (42) gives a triangular number (1237951 = T₁₅₇₃).

The spelling of 51993942 in words is "fifty-one million, nine hundred ninety-three thousand, nine hundred forty-two".