81008253 has 12 divisors (see below), whose sum is σ = 117103740. Its totient is φ = 53963136.

The previous prime is 81008243. The next prime is 81008273. The reversal of 81008253 is 35280018.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 63393444 + 17614809 = 7962^2 + 4197^2 .

It is not a de Polignac number, because 81008253 - 2¹³ = 81000061 is a prime.

It is a super-2 number, since 2×81008253² = 13124674108224018, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81008233) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12325 + ... + 17717.

It is an arithmetic number, because the mean of its divisors is an integer number (9758645).

Almost surely, 2^81008253 is an apocalyptic number.

It is an amenable number.

81008253 is a deficient number, since it is larger than the sum of its proper divisors (36095487).

81008253 is a wasteful number, since it uses less digits than its factorization.

81008253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7068 (or 7065 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 81008253 is about 9000.4584883216. The cubic root of 81008253 is about 432.6895655138.

The spelling of 81008253 in words is "eighty-one million, eight thousand, two hundred fifty-three".