51491280 has 80 divisors (see below), whose sum is σ = 161864640. Its totient is φ = 13538304.

The previous prime is 51491267. The next prime is 51491281. The reversal of 51491280 is 8219415.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51491281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16051 + ... + 18989.

It is an arithmetic number, because the mean of its divisors is an integer number (2023308).

Almost surely, 2^51491280 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51491280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80932320).

51491280 is an abundant number, since it is smaller than the sum of its proper divisors (110373360).

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

51491280 is a wasteful number, since it uses less digits than its factorization.

51491280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3028 (or 3022 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 51491280 is about 7175.7424702953. The cubic root of 51491280 is about 372.0299432482.

The spelling of 51491280 in words is "fifty-one million, four hundred ninety-one thousand, two hundred eighty".