51581166 has 80 divisors (see below), whose sum is σ = 130694784. Its totient is φ = 13287456.

The previous prime is 51581149. The next prime is 51581171. The reversal of 51581166 is 66118515.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1199541 + ... + 1199583.

Almost surely, 2^51581166 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51581166, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (65347392).

51581166 is an abundant number, since it is smaller than the sum of its proper divisors (79113618).

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

51581166 is an equidigital number, since it uses as much as digits as its factorization.

51581166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107 (or 68 counting only the distinct ones).

The product of its digits is 7200, while the sum is 33.

The square root of 51581166 is about 7182.0029239760. The cubic root of 51581166 is about 372.2462960231.

The spelling of 51581166 in words is "fifty-one million, five hundred eighty-one thousand, one hundred sixty-six".