81270225 has 27 divisors (see below), whose sum is σ = 145806609. Its totient is φ = 43272000.

The previous prime is 81270187. The next prime is 81270229. The reversal of 81270225 is 52207218.

The square root of 81270225 is 9015.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 4322241 + 76947984 = 2079^2 + 8772^2 .

It is a de Polignac number, because none of the positive numbers 2^k-81270225 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81270229) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 134925 + ... + 135525.

Almost surely, 2^81270225 is an apocalyptic number.

81270225 is the 9015-th square number.

81270225 is the 4508-th centered octagonal number.

It is an amenable number.

81270225 is a deficient number, since it is larger than the sum of its proper divisors (64536384).

81270225 is an equidigital number, since it uses as much as digits as its factorization.

81270225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1218 (or 609 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The cubic root of 81270225 is about 433.1554875062.

The spelling of 81270225 in words is "eighty-one million, two hundred seventy thousand, two hundred twenty-five".