81005253 has 32 divisors (see below), whose sum is σ = 127616256. Its totient is φ = 44748288.

The previous prime is 81005251. The next prime is 81005269. The reversal of 81005253 is 35250018.

It is not a de Polignac number, because 81005253 - 2¹ = 81005251 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81005251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 80751 + ... + 81747.

It is an arithmetic number, because the mean of its divisors is an integer number (3988008).

Almost surely, 2^81005253 is an apocalyptic number.

It is an amenable number.

81005253 is a deficient number, since it is larger than the sum of its proper divisors (46611003).

81005253 is a wasteful number, since it uses less digits than its factorization.

81005253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1133.

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 81005253 is about 9000.2918286020. The cubic root of 81005253 is about 432.6842241456.

The spelling of 81005253 in words is "eighty-one million, five thousand, two hundred fifty-three".