51161261 has 2 divisors, whose sum is σ = 51161262. Its totient is φ = 51161260.

The previous prime is 51161237. The next prime is 51161287. The reversal of 51161261 is 16216115.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37515625 + 13645636 = 6125^2 + 3694^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51161261 is a prime.

It is a super-2 number, since 2×51161261² = 5234949254220242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51161291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25580630 + 25580631.

It is an arithmetic number, because the mean of its divisors is an integer number (25580631).

Almost surely, 2^51161261 is an apocalyptic number.

It is an amenable number.

51161261 is a deficient number, since it is larger than the sum of its proper divisors (1).

51161261 is an equidigital number, since it uses as much as digits as its factorization.

51161261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 360, while the sum is 23.

The square root of 51161261 is about 7152.7100458498. The cubic root of 51161261 is about 371.2334317524.

Adding to 51161261 its reverse (16216115), we get a palindrome (67377376).

The spelling of 51161261 in words is "fifty-one million, one hundred sixty-one thousand, two hundred sixty-one".