51891017616 has 135 divisors (see below), whose sum is σ = 149173375377. Its totient is φ = 16838680320.

The previous prime is 51891017611. The next prime is 51891017627. The reversal of 51891017616 is 61671019815.

The square root of 51891017616 is 227796.

It is a perfect power (a square), and thus also a powerful number.

51891017616 is a `hidden beast` number, since 5 + 1 + 8 + 9 + 10 + 17 + 616 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2500400016 + 49390617600 = 50004^2 + 222240^2 .

It is not an unprimeable number, because it can be changed into a prime (51891017611) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 112075401 + ... + 112075863.

Almost surely, 2^51891017616 is an apocalyptic number.

51891017616 is the 227796-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51891017616

51891017616 is an abundant number, since it is smaller than the sum of its proper divisors (97282357761).

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

51891017616 is an equidigital number, since it uses as much as digits as its factorization.

51891017616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1022 (or 509 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 45.

The spelling of 51891017616 in words is "fifty-one billion, eight hundred ninety-one million, seventeen thousand, six hundred sixteen".