81408516 has 48 divisors (see below), whose sum is σ = 217534464. Its totient is φ = 23211936.

The previous prime is 81408499. The next prime is 81408517. The reversal of 81408516 is 61580418.

It is not an unprimeable number, because it can be changed into a prime (81408517) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71931 + ... + 73053.

It is an arithmetic number, because the mean of its divisors is an integer number (4531968).

Almost surely, 2^81408516 is an apocalyptic number.

It is an amenable number.

81408516 is an abundant number, since it is smaller than the sum of its proper divisors (136125948).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81408516 is a wasteful number, since it uses less digits than its factorization.

81408516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2000 (or 1998 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 33.

The square root of 81408516 is about 9022.6667898133. Note that the first 3 decimals coincide. The cubic root of 81408516 is about 433.4010368903.

The spelling of 81408516 in words is "eighty-one million, four hundred eight thousand, five hundred sixteen".