51617581 has 2 divisors, whose sum is σ = 51617582. Its totient is φ = 51617580.

The previous prime is 51617569. The next prime is 51617611. The reversal of 51617581 is 18571615.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39576681 + 12040900 = 6291^2 + 3470^2 .

It is a cyclic number.

It is not a de Polignac number, because 51617581 - 2⁷ = 51617453 is a prime.

It is a super-2 number, since 2×51617581² = 5328749336583122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51617521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25808790 + 25808791.

It is an arithmetic number, because the mean of its divisors is an integer number (25808791).

Almost surely, 2^51617581 is an apocalyptic number.

It is an amenable number.

51617581 is a deficient number, since it is larger than the sum of its proper divisors (1).

51617581 is an equidigital number, since it uses as much as digits as its factorization.

51617581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8400, while the sum is 34.

The square root of 51617581 is about 7184.5376330005. The cubic root of 51617581 is about 372.3338742437. Note that the first 3 decimals are identical.

The spelling of 51617581 in words is "fifty-one million, six hundred seventeen thousand, five hundred eighty-one".