81929761081 has 8 divisors (see below), whose sum is σ = 93802121280. Its totient is φ = 70099428048.

The previous prime is 81929761063. The next prime is 81929761103. The reversal of 81929761081 is 18016792918.

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

It is a cyclic number.

It is not a de Polignac number, because 81929761081 - 2¹⁹ = 81929236793 is a prime.

It is a super-2 number, since 2×81929761081² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81929761021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10502611 + ... + 10510408.

It is an arithmetic number, because the mean of its divisors is an integer number (11725265160).

Almost surely, 2^81929761081 is an apocalyptic number.

It is an amenable number.

81929761081 is a deficient number, since it is larger than the sum of its proper divisors (11872360199).

81929761081 is a wasteful number, since it uses less digits than its factorization.

81929761081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21013583.

The product of its (nonzero) digits is 435456, while the sum is 52.

The spelling of 81929761081 in words is "eighty-one billion, nine hundred twenty-nine million, seven hundred sixty-one thousand, eighty-one".