51387981844950 has 240 divisors, whose sum is σ = 145908655801920. Its totient is φ = 13403780052480.

The previous prime is 51387981844949. The next prime is 51387981844981. The reversal of 51387981844950 is 5944818978315.

It is a happy number.

51387981844950 is a `hidden beast` number, since 5 + 1 + 3 + 87 + 98 + 18 + 449 + 5 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 317613274 + ... + 317775026.

It is an arithmetic number, because the mean of its divisors is an integer number (607952732508).

Almost surely, 2^{51387981844950} is an apocalyptic number.

51387981844950 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 51387981844950, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72954327900960).

51387981844950 is an abundant number, since it is smaller than the sum of its proper divisors (94520673956970).

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

51387981844950 is a wasteful number, since it uses less digits than its factorization.

51387981844950 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163493 (or 163479 counting only the distinct ones).

The product of its (nonzero) digits is 348364800, while the sum is 72.

The spelling of 51387981844950 in words is "fifty-one trillion, three hundred eighty-seven billion, nine hundred eighty-one million, eight hundred forty-four thousand, nine hundred fifty".