81001895 has 32 divisors (see below), whose sum is σ = 108854592. Its totient is φ = 57480192.

The previous prime is 81001873. The next prime is 81001927. The reversal of 81001895 is 59810018.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 81001895 - 2⁶ = 81001831 is a prime.

It is a super-2 number, since 2×81001895² = 13122613987182050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 203837 + ... + 204233.

It is an arithmetic number, because the mean of its divisors is an integer number (3401706).

Almost surely, 2^81001895 is an apocalyptic number.

81001895 is a deficient number, since it is larger than the sum of its proper divisors (27852697).

81001895 is a wasteful number, since it uses less digits than its factorization.

81001895 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 531.

The product of its (nonzero) digits is 2880, while the sum is 32.

The square root of 81001895 is about 9000.1052771620. The cubic root of 81001895 is about 432.6782452177.

The spelling of 81001895 in words is "eighty-one million, one thousand, eight hundred ninety-five".