81019071 has 12 divisors (see below), whose sum is σ = 133745872. Its totient is φ = 46296576.

The previous prime is 81019067. The next prime is 81019091. The reversal of 81019071 is 17091018.

It is not a de Polignac number, because 81019071 - 2² = 81019067 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81019091) 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 11 ways as a sum of consecutive naturals, for example, 642946 + ... + 643071.

Almost surely, 2^81019071 is an apocalyptic number.

81019071 is a deficient number, since it is larger than the sum of its proper divisors (52726801).

81019071 is a wasteful number, since it uses less digits than its factorization.

81019071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1286030 (or 1286027 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 27.

The square root of 81019071 is about 9001.0594376440. The cubic root of 81019071 is about 432.7088253925.

It can be divided in two parts, 810 and 19071, that added together give a square (19881 = 141²).

The spelling of 81019071 in words is "eighty-one million, nineteen thousand, seventy-one".