81428184 has 24 divisors (see below), whose sum is σ = 220534860. Its totient is φ = 27142704.

The previous prime is 81428101. The next prime is 81428189. The reversal of 81428184 is 48182418.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81428189) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 565402 + ... + 565545.

Almost surely, 2^81428184 is an apocalyptic number.

It is an amenable number.

81428184 is an abundant number, since it is smaller than the sum of its proper divisors (139106676).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81428184 is a wasteful number, since it uses less digits than its factorization.

81428184 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1130959 (or 1130952 counting only the distinct ones).

The product of its digits is 16384, while the sum is 36.

The square root of 81428184 is about 9023.7566456548. The cubic root of 81428184 is about 433.4359367822.

The spelling of 81428184 in words is "eighty-one million, four hundred twenty-eight thousand, one hundred eighty-four".