81764073 has 10 divisors (see below), whose sum is σ = 122141514. Its totient is φ = 54509328.

The previous prime is 81764071. The next prime is 81764083. The reversal of 81764073 is 37046718.

81764073 is a `hidden beast` number, since 8 + 1 + 7 + 640 + 7 + 3 = 666.

It can be written as a sum of positive squares in only one way, i.e., 48274704 + 33489369 = 6948^2 + 5787^2 .

It is not a de Polignac number, because 81764073 - 2¹ = 81764071 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81764071) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 504636 + ... + 504797.

Almost surely, 2^81764073 is an apocalyptic number.

It is an amenable number.

81764073 is a deficient number, since it is larger than the sum of its proper divisors (40377441).

81764073 is a wasteful number, since it uses less digits than its factorization.

81764073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1009445 (or 1009436 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 36.

The square root of 81764073 is about 9042.3488652009. The cubic root of 81764073 is about 434.0310896060.

The spelling of 81764073 in words is "eighty-one million, seven hundred sixty-four thousand, seventy-three".