51581885294809 has 27 divisors (see below), whose sum is σ = 53707508246431. Its totient is φ = 49538354208560.

The previous prime is 51581885294791. The next prime is 51581885294837. The reversal of 51581885294809 is 90849258818515.

The square root of 51581885294809 is 7182053.

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

It can be written as a sum of positive squares in only one way, i.e., 27048289435209 + 24533595859600 = 5200797^2 + 4953140^2 .

It is not a de Polignac number, because 51581885294809 - 2²³ = 51581876906201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51581885294899) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 47279454354 + ... + 47279455444.

Almost surely, 2^{51581885294809} is an apocalyptic number.

51581885294809 is the 7182053-rd square number.

51581885294809 is the 3591027-th centered octagonal number.

It is an amenable number.

51581885294809 is a deficient number, since it is larger than the sum of its proper divisors (2125622951622).

51581885294809 is an frugal number, since it uses more digits than its factorization.

51581885294809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2694 (or 1347 counting only the distinct ones).

The product of its (nonzero) digits is 331776000, while the sum is 73.

The spelling of 51581885294809 in words is "fifty-one trillion, five hundred eighty-one billion, eight hundred eighty-five million, two hundred ninety-four thousand, eight hundred nine".