81015459978 has 8 divisors (see below), whose sum is σ = 162030919968. Its totient is φ = 27005153324.

The previous prime is 81015459953. The next prime is 81015459983. The reversal of 81015459978 is 87995451018.

It is a sphenic number, since it is the product of 3 distinct primes.

81015459978 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6751288326 + ... + 6751288337.

It is an arithmetic number, because the mean of its divisors is an integer number (20253864996).

Almost surely, 2^81015459978 is an apocalyptic number.

81015459978 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81015459978 is a wasteful number, since it uses less digits than its factorization.

81015459978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13502576668.

The product of its (nonzero) digits is 3628800, while the sum is 57.

The spelling of 81015459978 in words is "eighty-one billion, fifteen million, four hundred fifty-nine thousand, nine hundred seventy-eight".