81421353 has 24 divisors (see below), whose sum is σ = 128403912. Its totient is φ = 49413888.

The previous prime is 81421339. The next prime is 81421363. The reversal of 81421353 is 35312418.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 205209 + 81216144 = 453^2 + 9012^2 .

It is not a de Polignac number, because 81421353 - 2¹² = 81417257 is a prime.

It is a super-3 number, since 3×81421353³ (a number of 25 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81421363) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3775 + ... + 13307.

It is an arithmetic number, because the mean of its divisors is an integer number (5350163).

Almost surely, 2^81421353 is an apocalyptic number.

It is an amenable number.

81421353 is a deficient number, since it is larger than the sum of its proper divisors (46982559).

81421353 is a wasteful number, since it uses less digits than its factorization.

81421353 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9625 (or 9622 counting only the distinct ones).

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

The square root of 81421353 is about 9023.3781368177. The cubic root of 81421353 is about 433.4238161480.

The spelling of 81421353 in words is "eighty-one million, four hundred twenty-one thousand, three hundred fifty-three".