51321420 has 36 divisors (see below), whose sum is σ = 155675520. Its totient is φ = 13685664.

The previous prime is 51321401. The next prime is 51321421. The reversal of 51321420 is 2412315.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 51321393 and 51321402.

It is not an unprimeable number, because it can be changed into a prime (51321421) 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, 142380 + ... + 142739.

It is an arithmetic number, because the mean of its divisors is an integer number (4324320).

Almost surely, 2^51321420 is an apocalyptic number.

It is an amenable number.

51321420 is an abundant number, since it is smaller than the sum of its proper divisors (104354100).

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

51321420 is a wasteful number, since it uses less digits than its factorization.

51321420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285134 (or 285129 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 51321420 is about 7163.8969841840. The cubic root of 51321420 is about 371.6204071025.

Adding to 51321420 its reverse (2412315), we get a palindrome (53733735).

The spelling of 51321420 in words is "fifty-one million, three hundred twenty-one thousand, four hundred twenty".