51661312 has 80 divisors (see below), whose sum is σ = 111367872. Its totient is φ = 23879680.

The previous prime is 51661307. The next prime is 51661333. The reversal of 51661312 is 21316615.

It is a super-2 number, since 2×51661312² = 5337782315122688, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 482763 + ... + 482869.

Almost surely, 2^51661312 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 51661312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55683936).

51661312 is an abundant number, since it is smaller than the sum of its proper divisors (59706560).

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

51661312 is a wasteful number, since it uses less digits than its factorization.

51661312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189 (or 173 counting only the distinct ones).

The product of its digits is 1080, while the sum is 25.

The square root of 51661312 is about 7187.5803995503. The cubic root of 51661312 is about 372.4389930569.

Adding to 51661312 its reverse (21316615), we get a palindrome (72977927).

The spelling of 51661312 in words is "fifty-one million, six hundred sixty-one thousand, three hundred twelve".