51221510784 has 256 divisors, whose sum is σ = 158336640000. Its totient is φ = 16270543872.

The previous prime is 51221510783. The next prime is 51221510803. The reversal of 51221510784 is 48701512215.

It is a happy number.

51221510784 is a `hidden beast` number, since 51 + 2 + 21 + 510 + 78 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (51221510783) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24401767 + ... + 24403865.

It is an arithmetic number, because the mean of its divisors is an integer number (618502500).

Almost surely, 2^51221510784 is an apocalyptic number.

51221510784 is a gapful number since it is divisible by the number (54) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51221510784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (79168320000).

51221510784 is an abundant number, since it is smaller than the sum of its proper divisors (107115129216).

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

51221510784 is a wasteful number, since it uses less digits than its factorization.

51221510784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2452 (or 2434 counting only the distinct ones).

The product of its (nonzero) digits is 22400, while the sum is 36.

The spelling of 51221510784 in words is "fifty-one billion, two hundred twenty-one million, five hundred ten thousand, seven hundred eighty-four".