51217920000 has 1300 divisors, whose sum is σ = 216736153480. Its totient is φ = 11943936000.

The previous prime is 51217919971. The next prime is 51217920011. The reversal of 51217920000 is 2971215.

It is a tau number, because it is divible by the number of its divisors (1300).

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 99 ways as a sum of consecutive naturals, for example, 2695679991 + ... + 2695680009.

Almost surely, 2^51217920000 is an apocalyptic number.

51217920000 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 51217920000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108368076740).

51217920000 is an abundant number, since it is smaller than the sum of its proper divisors (165518233480).

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

51217920000 is an equidigital number, since it uses as much as digits as its factorization.

51217920000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88 (or 42 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The spelling of 51217920000 in words is "fifty-one billion, two hundred seventeen million, nine hundred twenty thousand".