81920101 has 4 divisors (see below), whose sum is σ = 81942400. Its totient is φ = 81897804.

The previous prime is 81920081. The next prime is 81920119. The reversal of 81920101 is 10102918.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81920101 - 2⁷ = 81919973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81920131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4191 + ... + 13468.

It is an arithmetic number, because the mean of its divisors is an integer number (20485600).

Almost surely, 2^81920101 is an apocalyptic number.

It is an amenable number.

81920101 is a deficient number, since it is larger than the sum of its proper divisors (22299).

81920101 is a wasteful number, since it uses less digits than its factorization.

81920101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22298.

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 81920101 is about 9050.9723787005. The cubic root of 81920101 is about 434.3069971422.

The spelling of 81920101 in words is "eighty-one million, nine hundred twenty thousand, one hundred one".