81672869 has 4 divisors (see below), whose sum is σ = 81735744. Its totient is φ = 81609996.

The previous prime is 81672863. The next prime is 81672883. The reversal of 81672869 is 96827618.

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 81672869 - 2²⁴ = 64895653 is a prime.

It is a super-2 number, since 2×81672869² = 13340915061382322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81672863) 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, 29447 + ... + 32100.

It is an arithmetic number, because the mean of its divisors is an integer number (20433936).

Almost surely, 2^81672869 is an apocalyptic number.

It is an amenable number.

81672869 is a deficient number, since it is larger than the sum of its proper divisors (62875).

81672869 is a wasteful number, since it uses less digits than its factorization.

81672869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62874.

The product of its digits is 290304, while the sum is 47.

The square root of 81672869 is about 9037.3042994026. The cubic root of 81672869 is about 433.8696491032.

The spelling of 81672869 in words is "eighty-one million, six hundred seventy-two thousand, eight hundred sixty-nine".