51317940 has 48 divisors (see below), whose sum is σ = 144809280. Its totient is φ = 13578240.

The previous prime is 51317911. The next prime is 51317941. The reversal of 51317940 is 4971315.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 51317898 and 51317907.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51317941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4596 + ... + 11124.

It is an arithmetic number, because the mean of its divisors is an integer number (3016860).

Almost surely, 2^51317940 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 51317940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72404640).

51317940 is an abundant number, since it is smaller than the sum of its proper divisors (93491340).

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

51317940 is a wasteful number, since it uses less digits than its factorization.

51317940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6672 (or 6670 counting only the distinct ones).

The product of its (nonzero) digits is 3780, while the sum is 30.

The square root of 51317940 is about 7163.6540955018. The cubic root of 51317940 is about 371.6120073073.

The spelling of 51317940 in words is "fifty-one million, three hundred seventeen thousand, nine hundred forty".