51493680 has 240 divisors, whose sum is σ = 209611584. Its totient is φ = 11059200.

The previous prime is 51493649. The next prime is 51493681. The reversal of 51493680 is 8639415.

51493680 = 1253² + 1254² + ... + 1284².

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (51493681) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 85380 + ... + 85980.

Almost surely, 2^51493680 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 51493680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104805792).

51493680 is an abundant number, since it is smaller than the sum of its proper divisors (158117904).

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

51493680 is a wasteful number, since it uses less digits than its factorization.

51493680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 644 (or 635 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 51493680 is about 7175.9096984285. The cubic root of 51493680 is about 372.0357232430.

The spelling of 51493680 in words is "fifty-one million, four hundred ninety-three thousand, six hundred eighty".