51257220552 has 112 divisors (see below), whose sum is σ = 145149066540. Its totient is φ = 16960762368.

The previous prime is 51257220541. The next prime is 51257220577. The reversal of 51257220552 is 25502275215.

51257220552 is a `hidden beast` number, since 5 + 12 + 5 + 72 + 20 + 552 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 43876005156 + 7381215396 = 209466^2 + 85914^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 766908 + ... + 831060.

Almost surely, 2^51257220552 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 51257220552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72574533270).

51257220552 is an abundant number, since it is smaller than the sum of its proper divisors (93891845988).

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

51257220552 is a wasteful number, since it uses less digits than its factorization.

51257220552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64314 (or 64295 counting only the distinct ones).

The product of its (nonzero) digits is 70000, while the sum is 36.

Adding to 51257220552 its reverse (25502275215), we get a palindrome (76759495767).

The spelling of 51257220552 in words is "fifty-one billion, two hundred fifty-seven million, two hundred twenty thousand, five hundred fifty-two".