81047681002 has 4 divisors (see below), whose sum is σ = 121571521506. Its totient is φ = 40523840500.

The previous prime is 81047680997. The next prime is 81047681023. The reversal of 81047681002 is 20018674018.

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., 51039394561 + 30008286441 = 225919^2 + 173229^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20261920249 + ... + 20261920252.

Almost surely, 2^81047681002 is an apocalyptic number.

81047681002 is a deficient number, since it is larger than the sum of its proper divisors (40523840504).

81047681002 is a wasteful number, since it uses less digits than its factorization.

81047681002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40523840503.

The product of its (nonzero) digits is 21504, while the sum is 37.

The spelling of 81047681002 in words is "eighty-one billion, forty-seven million, six hundred eighty-one thousand, two".