81677869 has 32 divisors (see below), whose sum is σ = 104186880. Its totient is φ = 62689536.

The previous prime is 81677857. The next prime is 81677887. The reversal of 81677869 is 96877618.

81677869 = 312² + 313² + ... + 650².

It is not a de Polignac number, because 81677869 - 2¹⁹ = 81153581 is a prime.

It is a super-2 number, since 2×81677869² = 13342548568762322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81677819) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 722757 + ... + 722869.

It is an arithmetic number, because the mean of its divisors is an integer number (3255840).

Almost surely, 2^81677869 is an apocalyptic number.

It is an amenable number.

81677869 is a deficient number, since it is larger than the sum of its proper divisors (22509011).

81677869 is a wasteful number, since it uses less digits than its factorization.

81677869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206 (or 180 counting only the distinct ones).

The product of its digits is 1016064, while the sum is 52.

The square root of 81677869 is about 9037.5809263320. The cubic root of 81677869 is about 433.8785027328.

The spelling of 81677869 in words is "eighty-one million, six hundred seventy-seven thousand, eight hundred sixty-nine".