81725511 has 16 divisors (see below), whose sum is σ = 131860224. Its totient is φ = 43953024.

The previous prime is 81725491. The next prime is 81725521. The reversal of 81725511 is 11552718.

It is not a de Polignac number, because 81725511 - 2⁶ = 81725447 is a prime.

It is a super-2 number, since 2×81725511² = 13358118296422242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81725521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 114105 + ... + 114818.

It is an arithmetic number, because the mean of its divisors is an integer number (8241264).

Almost surely, 2^81725511 is an apocalyptic number.

81725511 is a deficient number, since it is larger than the sum of its proper divisors (50134713).

81725511 is a wasteful number, since it uses less digits than its factorization.

81725511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228950.

The product of its digits is 2800, while the sum is 30.

The square root of 81725511 is about 9040.2163137836. The cubic root of 81725511 is about 433.9628455384.

The spelling of 81725511 in words is "eighty-one million, seven hundred twenty-five thousand, five hundred eleven".