81443021 has 8 divisors (see below), whose sum is σ = 88917888. Its totient is φ = 73980000.

The previous prime is 81443009. The next prime is 81443029. The reversal of 81443021 is 12034418.

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 81443021 - 2¹⁸ = 81180877 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 (81443029) 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, 17756 + ... + 21866.

It is an arithmetic number, because the mean of its divisors is an integer number (11114736).

Almost surely, 2^81443021 is an apocalyptic number.

It is an amenable number.

81443021 is a deficient number, since it is larger than the sum of its proper divisors (7474867).

81443021 is a wasteful number, since it uses less digits than its factorization.

81443021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5923.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 81443021 is about 9024.5787159291. The cubic root of 81443021 is about 433.4622605852.

Adding to 81443021 its reverse (12034418), we get a palindrome (93477439).

The spelling of 81443021 in words is "eighty-one million, four hundred forty-three thousand, twenty-one".