51439600809 has 81 divisors (see below), whose sum is σ = 82452387927. Its totient is φ = 30896011872.

The previous prime is 51439600789. The next prime is 51439600837. The reversal of 51439600809 is 90800693415.

It is a happy number.

The square root of 51439600809 is 226803.

It is a perfect power (a square), and thus also a powerful number.

51439600809 is a `hidden beast` number, since 5 + 1 + 4 + 39 + 600 + 8 + 0 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 46792179225 + 4647421584 = 216315^2 + 68172^2 .

It is not a de Polignac number, because 51439600809 - 2²¹ = 51437503657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51439600859) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 297338647 + ... + 297338819.

Almost surely, 2^51439600809 is an apocalyptic number.

51439600809 is the 226803-rd square number.

51439600809 is the 113402-nd centered octagonal number.

It is an amenable number.

51439600809 is a deficient number, since it is larger than the sum of its proper divisors (31012787118).

51439600809 is a wasteful number, since it uses less digits than its factorization.

51439600809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436 (or 218 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The spelling of 51439600809 in words is "fifty-one billion, four hundred thirty-nine million, six hundred thousand, eight hundred nine".