51191420 has 96 divisors (see below), whose sum is σ = 131870592. Its totient is φ = 16293888.

The previous prime is 51191419. The next prime is 51191429. The reversal of 51191420 is 2419115.

It is a happy number.

It is a super-2 number, since 2×51191420² = 5241122963232800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51191429) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 325982 + ... + 326138.

It is an arithmetic number, because the mean of its divisors is an integer number (1373652).

Almost surely, 2^51191420 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 51191420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (65935296).

51191420 is an abundant number, since it is smaller than the sum of its proper divisors (80679172).

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

51191420 is a wasteful number, since it uses less digits than its factorization.

51191420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327 (or 325 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 23.

The square root of 51191420 is about 7154.8179571531. The cubic root of 51191420 is about 371.3063634302.

The spelling of 51191420 in words is "fifty-one million, one hundred ninety-one thousand, four hundred twenty".