81235951 has 2 divisors, whose sum is σ = 81235952. Its totient is φ = 81235950.

The previous prime is 81235943. The next prime is 81235991. The reversal of 81235951 is 15953218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81235951 - 2³ = 81235943 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81235991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40617975 + 40617976.

It is an arithmetic number, because the mean of its divisors is an integer number (40617976).

Almost surely, 2^81235951 is an apocalyptic number.

81235951 is a deficient number, since it is larger than the sum of its proper divisors (1).

81235951 is an equidigital number, since it uses as much as digits as its factorization.

81235951 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10800, while the sum is 34.

The square root of 81235951 is about 9013.0988566641. The cubic root of 81235951 is about 433.0945875531.

It can be divided in two parts, 812 and 35951, that added together give a palindrome (36763).

The spelling of 81235951 in words is "eighty-one million, two hundred thirty-five thousand, nine hundred fifty-one".