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51312020 = 2252988469
BaseRepresentation
bin1100001110111…
…1010110010100
310120112220212012
43003233112110
5101113441040
65031443352
71162100504
oct303572624
9116486765
1051312020
1126a67531
1215226558
13a827656
146b59a04
154788865
hex30ef594

51312020 has 24 divisors (see below), whose sum is σ = 111472200. Its totient is φ = 19816832.

The previous prime is 51311993. The next prime is 51312031. The reversal of 51312020 is 2021315.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 16289296 + 35022724 = 4036^2 + 5918^2 .

It is a junction number, because it is equal to n+sod(n) for n = 51311986 and 51312004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43655 + ... + 44814.

It is an arithmetic number, because the mean of its divisors is an integer number (4644675).

Almost surely, 251312020 is an apocalyptic number.

It is an amenable number.

51312020 is an abundant number, since it is smaller than the sum of its proper divisors (60160180).

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

51312020 is a wasteful number, since it uses less digits than its factorization.

51312020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88507 (or 88505 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 51312020 is about 7163.2408866378. The cubic root of 51312020 is about 371.5977171280.

Adding to 51312020 its reverse (2021315), we get a palindrome (53333335).

The spelling of 51312020 in words is "fifty-one million, three hundred twelve thousand, twenty".

Divisors: 1 2 4 5 10 20 29 58 116 145 290 580 88469 176938 353876 442345 884690 1769380 2565601 5131202 10262404 12828005 25656010 51312020