81067921 has 8 divisors (see below), whose sum is σ = 88617600. Its totient is φ = 73548240.

The previous prime is 81067907. The next prime is 81067937. The reversal of 81067921 is 12976018.

It is a happy number.

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 81067921 - 2¹⁹ = 80543633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81067321) 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, 1641 + ... + 12838.

It is an arithmetic number, because the mean of its divisors is an integer number (11077200).

Almost surely, 2^81067921 is an apocalyptic number.

It is an amenable number.

81067921 is a deficient number, since it is larger than the sum of its proper divisors (7549679).

81067921 is a wasteful number, since it uses less digits than its factorization.

81067921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14999.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 81067921 is about 9003.7725981946. The cubic root of 81067921 is about 432.7957743827.

The spelling of 81067921 in words is "eighty-one million, sixty-seven thousand, nine hundred twenty-one".