51235661252281 has 81 divisors (see below), whose sum is σ = 59402689298253. Its totient is φ = 44156854304640.

The previous prime is 51235661252239. The next prime is 51235661252291. The reversal of 51235661252281 is 18225216653215.

It is a happy number.

The square root of 51235661252281 is 7157909.

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

It can be written as a sum of positive squares in 4 ways, for example, as 33545931853225 + 17689729399056 = 5791885^2 + 4205916^2 .

It is not a de Polignac number, because 51235661252281 - 2²¹ = 51235659155129 is a prime.

It is a super-2 number, since 2×51235661252281² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

Its product of digits (1728000) is a multiple of the sum of its prime divisors (500).

It is not an unprimeable number, because it can be changed into a prime (51235661252201) 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, 125270565205 + ... + 125270565613.

Almost surely, 2^{51235661252281} is an apocalyptic number.

51235661252281 is the 7157909-th square number.

51235661252281 is the 3578955-th centered octagonal number.

It is an amenable number.

51235661252281 is a deficient number, since it is larger than the sum of its proper divisors (8167028045972).

51235661252281 is an frugal number, since it uses more digits than its factorization.

51235661252281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1000 (or 500 counting only the distinct ones).

The product of its digits is 1728000, while the sum is 49.

The spelling of 51235661252281 in words is "fifty-one trillion, two hundred thirty-five billion, six hundred sixty-one million, two hundred fifty-two thousand, two hundred eighty-one".