81718461 has 12 divisors (see below), whose sum is σ = 128768640. Its totient is φ = 49526280.

The previous prime is 81718457. The next prime is 81718489. The reversal of 81718461 is 16481718.

It is not a de Polignac number, because 81718461 - 2² = 81718457 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81718451) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 412621 + ... + 412818.

It is an arithmetic number, because the mean of its divisors is an integer number (10730720).

Almost surely, 2^81718461 is an apocalyptic number.

It is an amenable number.

81718461 is a deficient number, since it is larger than the sum of its proper divisors (47050179).

81718461 is a wasteful number, since it uses less digits than its factorization.

81718461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 825456 (or 825453 counting only the distinct ones).

The product of its digits is 10752, while the sum is 36.

The square root of 81718461 is about 9039.8263810761. The cubic root of 81718461 is about 433.9503666686.

The spelling of 81718461 in words is "eighty-one million, seven hundred eighteen thousand, four hundred sixty-one".