51515421100 has 288 divisors, whose sum is σ = 135480703680. Its totient is φ = 16754688000.

The previous prime is 51515421077. The next prime is 51515421101. The reversal of 51515421100 is 112451515.

It is a super-2 number, since 2×51515421100² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is not an unprimeable number, because it can be changed into a prime (51515421101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 63677496 + ... + 63678304.

It is an arithmetic number, because the mean of its divisors is an integer number (470419110).

Almost surely, 2^51515421100 is an apocalyptic number.

51515421100 is a gapful number since it is divisible by the number (50) 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 51515421100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67740351840).

51515421100 is an abundant number, since it is smaller than the sum of its proper divisors (83965282580).

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

51515421100 is a wasteful number, since it uses less digits than its factorization.

51515421100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 981 (or 974 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 25.

Adding to 51515421100 its reverse (112451515), we get a palindrome (51627872615).

The spelling of 51515421100 in words is "fifty-one billion, five hundred fifteen million, four hundred twenty-one thousand, one hundred".