51405312 has 120 divisors (see below), whose sum is σ = 159538896. Its totient is φ = 14665728.

The previous prime is 51405271. The next prime is 51405337. The reversal of 51405312 is 21350415.

It is a super-2 number, since 2×51405312² = 5285012203634688, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 74923 + ... + 75605.

Almost surely, 2^51405312 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 51405312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (79769448).

51405312 is an abundant number, since it is smaller than the sum of its proper divisors (108133584).

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

51405312 is an equidigital number, since it uses as much as digits as its factorization.

51405312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 718 (or 695 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 51405312 is about 7169.7497864291. The cubic root of 51405312 is about 371.8227852871.

Adding to 51405312 its reverse (21350415), we get a palindrome (72755727).

The spelling of 51405312 in words is "fifty-one million, four hundred five thousand, three hundred twelve".