81439153 has 4 divisors (see below), whose sum is σ = 81865728. Its totient is φ = 81012580.

The previous prime is 81439123. The next prime is 81439181. The reversal of 81439153 is 35193418.

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 a cyclic number.

It is not a de Polignac number, because 81439153 - 2¹⁷ = 81308081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81439123) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 213001 + ... + 213382.

It is an arithmetic number, because the mean of its divisors is an integer number (20466432).

Almost surely, 2^81439153 is an apocalyptic number.

It is an amenable number.

81439153 is a deficient number, since it is larger than the sum of its proper divisors (426575).

81439153 is a wasteful number, since it uses less digits than its factorization.

81439153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426574.

The product of its digits is 12960, while the sum is 34.

The square root of 81439153 is about 9024.3644097521. The cubic root of 81439153 is about 433.4553982884.

The spelling of 81439153 in words is "eighty-one million, four hundred thirty-nine thousand, one hundred fifty-three".