81939155251955 has 16 divisors (see below), whose sum is σ = 100821225960000. Its totient is φ = 63891546032640.

The previous prime is 81939155251939. The next prime is 81939155252029. The reversal of 81939155251955 is 55915255193918.

It is not a de Polignac number, because 81939155251955 - 2⁴ = 81939155251939 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 190301255 + ... + 190731344.

It is an arithmetic number, because the mean of its divisors is an integer number (6301326622500).

Almost surely, 2^{81939155251955} is an apocalyptic number.

81939155251955 is a deficient number, since it is larger than the sum of its proper divisors (18882070708045).

81939155251955 is a wasteful number, since it uses less digits than its factorization.

81939155251955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381033694.

The product of its digits is 109350000, while the sum is 68.

The spelling of 81939155251955 in words is "eighty-one trillion, nine hundred thirty-nine billion, one hundred fifty-five million, two hundred fifty-one thousand, nine hundred fifty-five".