51821480 has 48 divisors (see below), whose sum is σ = 118723860. Its totient is φ = 20357120.

The previous prime is 51821479. The next prime is 51821489. The reversal of 51821480 is 8412815.

It can be written as a sum of positive squares in 2 ways, for example, as 48413764 + 3407716 = 6958^2 + 1846^2 .

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (51821489) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 201512 + ... + 201768.

Almost surely, 2^51821480 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 51821480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (59361930).

51821480 is an abundant number, since it is smaller than the sum of its proper divisors (66902380).

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

51821480 is a wasteful number, since it uses less digits than its factorization.

51821480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410 (or 335 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 29.

The square root of 51821480 is about 7198.7137740016. The cubic root of 51821480 is about 372.8234926896.

The spelling of 51821480 in words is "fifty-one million, eight hundred twenty-one thousand, four hundred eighty".