81401493 has 4 divisors (see below), whose sum is σ = 108535328. Its totient is φ = 54267660.

The previous prime is 81401477. The next prime is 81401501. The reversal of 81401493 is 39410418.

It is a happy number.

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 not a de Polignac number, because 81401493 - 2⁴ = 81401477 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81401493.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81401413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13566913 + ... + 13566918.

It is an arithmetic number, because the mean of its divisors is an integer number (27133832).

Almost surely, 2^81401493 is an apocalyptic number.

It is an amenable number.

81401493 is a deficient number, since it is larger than the sum of its proper divisors (27133835).

81401493 is a wasteful number, since it uses less digits than its factorization.

81401493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27133834.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 81401493 is about 9022.2775949313. The cubic root of 81401493 is about 433.3885735627.

The spelling of 81401493 in words is "eighty-one million, four hundred one thousand, four hundred ninety-three".