81680455 has 4 divisors (see below), whose sum is σ = 98016552. Its totient is φ = 65344360.

The previous prime is 81680453. The next prime is 81680491. The reversal of 81680455 is 55408618.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 81680455 - 2¹ = 81680453 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 (81680453) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8168041 + ... + 8168050.

It is an arithmetic number, because the mean of its divisors is an integer number (24504138).

Almost surely, 2^81680455 is an apocalyptic number.

81680455 is a deficient number, since it is larger than the sum of its proper divisors (16336097).

81680455 is a wasteful number, since it uses less digits than its factorization.

81680455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16336096.

The product of its (nonzero) digits is 38400, while the sum is 37.

The square root of 81680455 is about 9037.7239944579. The cubic root of 81680455 is about 433.8830816882.

The spelling of 81680455 in words is "eighty-one million, six hundred eighty thousand, four hundred fifty-five".