81884401 has 3 divisors (see below), whose sum is σ = 81893451. Its totient is φ = 81875352.

The previous prime is 81884399. The next prime is 81884419. The reversal of 81884401 is 10448818.

It is a happy number.

The square root of 81884401 is 9049.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 68046001 + 13838400 = 8249^2 + 3720^2 .

It is not a de Polignac number, because 81884401 - 2¹ = 81884399 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81824401) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 4525 + ... + 13573.

It is an arithmetic number, because the mean of its divisors is an integer number (27297817).

Almost surely, 2^81884401 is an apocalyptic number.

81884401 is the 9049-th square number.

81884401 is the 4525-th centered octagonal number.

It is an amenable number.

81884401 is a deficient number, since it is larger than the sum of its proper divisors (9050).

81884401 is an frugal number, since it uses more digits than its factorization.

81884401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18098 (or 9049 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 34.

The cubic root of 81884401 is about 434.2438990241.

The spelling of 81884401 in words is "eighty-one million, eight hundred eighty-four thousand, four hundred one".