51781436 has 54 divisors (see below), whose sum is σ = 108678024. Its totient is φ = 21520800.

The previous prime is 51781421. The next prime is 51781447. The reversal of 51781436 is 63418715.

It is a super-2 number, since 2×51781436² = 5362634228444192, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 51781396 and 51781405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 729281 + ... + 729351.

It is an arithmetic number, because the mean of its divisors is an integer number (2012556).

Almost surely, 2^51781436 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 51781436, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (54339012).

51781436 is an abundant number, since it is smaller than the sum of its proper divisors (56896588).

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

51781436 is a wasteful number, since it uses less digits than its factorization.

51781436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211 (or 141 counting only the distinct ones).

The product of its digits is 20160, while the sum is 35.

The square root of 51781436 is about 7195.9319062926. The cubic root of 51781436 is about 372.7274373406.

The spelling of 51781436 in words is "fifty-one million, seven hundred eighty-one thousand, four hundred thirty-six".