81353421 has 12 divisors (see below), whose sum is σ = 123695520. Its totient is φ = 51381000.

The previous prime is 81353407. The next prime is 81353429. The reversal of 81353421 is 12435318.

It is a happy number.

It is not a de Polignac number, because 81353421 - 2¹⁵ = 81320653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81353429) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 237705 + ... + 238046.

It is an arithmetic number, because the mean of its divisors is an integer number (10307960).

Almost surely, 2^81353421 is an apocalyptic number.

It is an amenable number.

81353421 is a deficient number, since it is larger than the sum of its proper divisors (42342099).

81353421 is a wasteful number, since it uses less digits than its factorization.

81353421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 475776 (or 475773 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 81353421 is about 9019.6131291758. The cubic root of 81353421 is about 433.3032436043.

Adding to 81353421 its reverse (12435318), we get a palindrome (93788739).

The spelling of 81353421 in words is "eighty-one million, three hundred fifty-three thousand, four hundred twenty-one".