51221171500 has 48 divisors (see below), whose sum is σ = 112579740000. Its totient is φ = 20357937600.

The previous prime is 51221171471. The next prime is 51221171579. The reversal of 51221171500 is 517112215.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 247750 + ... + 404749.

It is an arithmetic number, because the mean of its divisors is an integer number (2345411250).

Almost surely, 2^51221171500 is an apocalyptic number.

51221171500 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

51221171500 is an abundant number, since it is smaller than the sum of its proper divisors (61358568500).

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

51221171500 is a wasteful number, since it uses less digits than its factorization.

51221171500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 652675 (or 652663 counting only the distinct ones).

The product of its (nonzero) digits is 700, while the sum is 25.

Adding to 51221171500 its reverse (517112215), we get a palindrome (51738283715).

The spelling of 51221171500 in words is "fifty-one billion, two hundred twenty-one million, one hundred seventy-one thousand, five hundred".