81228657923 has 16 divisors (see below), whose sum is σ = 94556876544. Its totient is φ = 68336364960.

The previous prime is 81228657869. The next prime is 81228657947. The reversal of 81228657923 is 32975682218.

It is a cyclic number.

It is not a de Polignac number, because 81228657923 - 2⁶ = 81228657859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81228657623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4265 + ... + 403082.

It is an arithmetic number, because the mean of its divisors is an integer number (5909804784).

Almost surely, 2^81228657923 is an apocalyptic number.

81228657923 is a deficient number, since it is larger than the sum of its proper divisors (13328218621).

81228657923 is a wasteful number, since it uses less digits than its factorization.

81228657923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407882.

The product of its digits is 2903040, while the sum is 53.

The spelling of 81228657923 in words is "eighty-one billion, two hundred twenty-eight million, six hundred fifty-seven thousand, nine hundred twenty-three".