81229769 has 4 divisors (see below), whose sum is σ = 85505040. Its totient is φ = 76954500.

The previous prime is 81229747. The next prime is 81229781. The reversal of 81229769 is 96792218.

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 a cyclic number.

It is not a de Polignac number, because 81229769 - 2¹⁶ = 81164233 is a prime.

It is a super-2 number, since 2×81229769² = 13196550743586722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81229789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2137607 + ... + 2137644.

It is an arithmetic number, because the mean of its divisors is an integer number (21376260).

Almost surely, 2^81229769 is an apocalyptic number.

It is an amenable number.

81229769 is a deficient number, since it is larger than the sum of its proper divisors (4275271).

81229769 is a wasteful number, since it uses less digits than its factorization.

81229769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4275270.

The product of its digits is 108864, while the sum is 44.

The square root of 81229769 is about 9012.7559048273. The cubic root of 81229769 is about 433.0836012077.

The spelling of 81229769 in words is "eighty-one million, two hundred twenty-nine thousand, seven hundred sixty-nine".