51216420 has 48 divisors (see below), whose sum is σ = 143716608. Its totient is φ = 13628160.

The previous prime is 51216409. The next prime is 51216437. The reversal of 51216420 is 2461215.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54192 + ... + 55128.

It is an arithmetic number, because the mean of its divisors is an integer number (2994096).

Almost surely, 2^51216420 is an apocalyptic number.

It is an amenable number.

51216420 is an abundant number, since it is smaller than the sum of its proper divisors (92500188).

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

51216420 is a wasteful number, since it uses less digits than its factorization.

51216420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1860 (or 1858 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 51216420 is about 7156.5648184028. The cubic root of 51216420 is about 371.3667977008.

Adding to 51216420 its reverse (2461215), we get a palindrome (53677635).

The spelling of 51216420 in words is "fifty-one million, two hundred sixteen thousand, four hundred twenty".