81578953 has 4 divisors (see below), whose sum is σ = 85125888. Its totient is φ = 78032020.

The previous prime is 81578947. The next prime is 81578963. The reversal of 81578953 is 35987518.

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 81578953 - 2¹³ = 81570761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81578923) 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, 1773433 + ... + 1773478.

It is an arithmetic number, because the mean of its divisors is an integer number (21281472).

Almost surely, 2^81578953 is an apocalyptic number.

It is an amenable number.

81578953 is a deficient number, since it is larger than the sum of its proper divisors (3546935).

81578953 is a wasteful number, since it uses less digits than its factorization.

81578953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3546934.

The product of its digits is 302400, while the sum is 46.

The square root of 81578953 is about 9032.1067863484. The cubic root of 81578953 is about 433.7032824303.

The spelling of 81578953 in words is "eighty-one million, five hundred seventy-eight thousand, nine hundred fifty-three".