81015287954 has 4 divisors (see below), whose sum is σ = 121522931934. Its totient is φ = 40507643976.

The previous prime is 81015287939. The next prime is 81015287993. The reversal of 81015287954 is 45978251018.

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

It can be written as a sum of positive squares in only one way, i.e., 80073718729 + 941569225 = 282973^2 + 30685^2 .

It is a super-2 number, since 2×81015287954² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20253821987 + ... + 20253821990.

Almost surely, 2^81015287954 is an apocalyptic number.

81015287954 is a deficient number, since it is larger than the sum of its proper divisors (40507643980).

81015287954 is a wasteful number, since it uses less digits than its factorization.

81015287954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40507643979.

The product of its (nonzero) digits is 806400, while the sum is 50.

The spelling of 81015287954 in words is "eighty-one billion, fifteen million, two hundred eighty-seven thousand, nine hundred fifty-four".