81356263 has 4 divisors (see below), whose sum is σ = 81587088. Its totient is φ = 81125440.

The previous prime is 81356257. The next prime is 81356269. The reversal of 81356263 is 36265318.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (81356257) and next prime (81356269).

It is a cyclic number.

It is not a de Polignac number, because 81356263 - 2⁹ = 81355751 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81356269) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 114883 + ... + 115588.

It is an arithmetic number, because the mean of its divisors is an integer number (20396772).

Almost surely, 2^81356263 is an apocalyptic number.

81356263 is a deficient number, since it is larger than the sum of its proper divisors (230825).

81356263 is a wasteful number, since it uses less digits than its factorization.

81356263 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230824.

The product of its digits is 25920, while the sum is 34.

The square root of 81356263 is about 9019.7706733597. The cubic root of 81356263 is about 433.3082892167.

The spelling of 81356263 in words is "eighty-one million, three hundred fifty-six thousand, two hundred sixty-three".