81887369 has 4 divisors (see below), whose sum is σ = 82682496. Its totient is φ = 81092244.

The previous prime is 81887363. The next prime is 81887381. The reversal of 81887369 is 96378818.

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, and also an emirpimes, since its reverse is a distinct semiprime: 96378818 = 2 ⋅48189409.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81887369 is a prime.

It is a super-2 number, since 2×81887369² = 13411082403484322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81887363) 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, 397409 + ... + 397614.

It is an arithmetic number, because the mean of its divisors is an integer number (20670624).

Almost surely, 2^81887369 is an apocalyptic number.

It is an amenable number.

81887369 is a deficient number, since it is larger than the sum of its proper divisors (795127).

81887369 is a wasteful number, since it uses less digits than its factorization.

81887369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 795126.

The product of its digits is 580608, while the sum is 50.

The square root of 81887369 is about 9049.1639945356. The cubic root of 81887369 is about 434.2491455273.

The spelling of 81887369 in words is "eighty-one million, eight hundred eighty-seven thousand, three hundred sixty-nine".