81942253 has 2 divisors, whose sum is σ = 81942254. Its totient is φ = 81942252.

The previous prime is 81942251. The next prime is 81942257. The reversal of 81942253 is 35224918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78907689 + 3034564 = 8883^2 + 1742^2 .

It is a cyclic number.

It is not a de Polignac number, because 81942253 - 2¹ = 81942251 is a prime.

Together with 81942251, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81942251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40971126 + 40971127.

It is an arithmetic number, because the mean of its divisors is an integer number (40971127).

Almost surely, 2^81942253 is an apocalyptic number.

It is an amenable number.

81942253 is a deficient number, since it is larger than the sum of its proper divisors (1).

81942253 is an equidigital number, since it uses as much as digits as its factorization.

81942253 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 34.

The square root of 81942253 is about 9052.1960319030. The cubic root of 81942253 is about 434.3461405736.

The spelling of 81942253 in words is "eighty-one million, nine hundred forty-two thousand, two hundred fifty-three".