81577025 has 6 divisors (see below), whose sum is σ = 101155542. Its totient is φ = 65261600.

The previous prime is 81576997. The next prime is 81577037. The reversal of 81577025 is 52077518.

It is a Cunningham number, because it is equal to 9032²+1.

It can be written as a sum of positive squares in 3 ways, for example, as 1 + 81577024 = 1^2 + 9032^2 .

It is not a de Polignac number, because 81577025 - 2⁸ = 81576769 is a prime.

It is a super-2 number, since 2×81577025² = 13309622015701250, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 1631516 + ... + 1631565.

It is an arithmetic number, because the mean of its divisors is an integer number (16859257).

Almost surely, 2^81577025 is an apocalyptic number.

It is an amenable number.

81577025 is a deficient number, since it is larger than the sum of its proper divisors (19578517).

81577025 is a wasteful number, since it uses less digits than its factorization.

81577025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3263091 (or 3263086 counting only the distinct ones).

The product of its (nonzero) digits is 19600, while the sum is 35.

The square root of 81577025 is about 9032.0000553587. Note that the first 4 decimals coincide. The cubic root of 81577025 is about 433.6998657545.

The spelling of 81577025 in words is "eighty-one million, five hundred seventy-seven thousand, twenty-five".