81884661 has 16 divisors (see below), whose sum is σ = 118891200. Its totient is φ = 49932288.

The previous prime is 81884657. The next prime is 81884711. The reversal of 81884661 is 16648818.

It is not a de Polignac number, because 81884661 - 2² = 81884657 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81884651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23116 + ... + 26421.

It is an arithmetic number, because the mean of its divisors is an integer number (7430700).

Almost surely, 2^81884661 is an apocalyptic number.

It is an amenable number.

81884661 is a deficient number, since it is larger than the sum of its proper divisors (37006539).

81884661 is a wasteful number, since it uses less digits than its factorization.

81884661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49588.

The product of its digits is 73728, while the sum is 42.

The square root of 81884661 is about 9049.0143662169. The cubic root of 81884661 is about 434.2443586285.

The spelling of 81884661 in words is "eighty-one million, eight hundred eighty-four thousand, six hundred sixty-one".