51809111 has 2 divisors, whose sum is σ = 51809112. Its totient is φ = 51809110.

The previous prime is 51809101. The next prime is 51809129. The reversal of 51809111 is 11190815.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51809111 is a prime.

It is a super-2 number, since 2×51809111² = 5368367965220642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51809101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25904555 + 25904556.

It is an arithmetic number, because the mean of its divisors is an integer number (25904556).

Almost surely, 2^51809111 is an apocalyptic number.

51809111 is a deficient number, since it is larger than the sum of its proper divisors (1).

51809111 is an equidigital number, since it uses as much as digits as its factorization.

51809111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 26.

The square root of 51809111 is about 7197.8546109240. The cubic root of 51809111 is about 372.7938278947.

Adding to 51809111 its reverse (11190815), we get a palindrome (62999926).

The spelling of 51809111 in words is "fifty-one million, eight hundred nine thousand, one hundred eleven".