51861222000 has 1600 divisors, whose sum is σ = 235934899200. Its totient is φ = 10712217600.

The previous prime is 51861221977. The next prime is 51861222011. The reversal of 51861222000 is 22216815.

It is a happy number.

51861222000 is a `hidden beast` number, since 518 + 6 + 122 + 20 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 624833959 + ... + 624834041.

It is an arithmetic number, because the mean of its divisors is an integer number (147459312).

Almost surely, 2^51861222000 is an apocalyptic number.

51861222000 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 51861222000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117967449600).

51861222000 is an abundant number, since it is smaller than the sum of its proper divisors (184073677200).

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

51861222000 is a wasteful number, since it uses less digits than its factorization.

51861222000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

Adding to 51861222000 its reverse (22216815), we get a palindrome (51883438815).

The spelling of 51861222000 in words is "fifty-one billion, eight hundred sixty-one million, two hundred twenty-two thousand".