51220345540 has 192 divisors, whose sum is σ = 139617354240. Its totient is φ = 15328051200.

The previous prime is 51220345513. The next prime is 51220345549. The reversal of 51220345540 is 4554302215.

It is a super-3 number, since 3×51220345540³ (a number of 33 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (51220345549) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 24239524 + ... + 24241636.

It is an arithmetic number, because the mean of its divisors is an integer number (727173720).

Almost surely, 2^51220345540 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 51220345540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69808677120).

51220345540 is an abundant number, since it is smaller than the sum of its proper divisors (88397008700).

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

51220345540 is a wasteful number, since it uses less digits than its factorization.

51220345540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2862 (or 2860 counting only the distinct ones).

The product of its (nonzero) digits is 24000, while the sum is 31.

Adding to 51220345540 its reverse (4554302215), we get a palindrome (55774647755).

The spelling of 51220345540 in words is "fifty-one billion, two hundred twenty million, three hundred forty-five thousand, five hundred forty".