81667405881429 has 32 divisors (see below), whose sum is σ = 111852251481600. Its totient is φ = 52981315333440.

The previous prime is 81667405881427. The next prime is 81667405881461. The reversal of 81667405881429 is 92418850476618.

It is not a de Polignac number, because 81667405881429 - 2¹ = 81667405881427 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81667405881427) 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, 20707774 + ... + 24334064.

It is an arithmetic number, because the mean of its divisors is an integer number (3495382858800).

Almost surely, 2^{81667405881429} is an apocalyptic number.

It is an amenable number.

81667405881429 is a deficient number, since it is larger than the sum of its proper divisors (30184845600171).

81667405881429 is a wasteful number, since it uses less digits than its factorization.

81667405881429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3627505.

The product of its (nonzero) digits is 185794560, while the sum is 69.

The spelling of 81667405881429 in words is "eighty-one trillion, six hundred sixty-seven billion, four hundred five million, eight hundred eighty-one thousand, four hundred twenty-nine".