81400236 has 12 divisors (see below), whose sum is σ = 189933912. Its totient is φ = 27133408.

The previous prime is 81400223. The next prime is 81400271. The reversal of 81400236 is 63200418.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3391665 + ... + 3391688.

It is an arithmetic number, because the mean of its divisors is an integer number (15827826).

Almost surely, 2^81400236 is an apocalyptic number.

It is an amenable number.

81400236 is an abundant number, since it is smaller than the sum of its proper divisors (108533676).

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

81400236 is a wasteful number, since it uses less digits than its factorization.

81400236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6783360 (or 6783358 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 81400236 is about 9022.2079337599. The cubic root of 81400236 is about 433.3863427590.

The spelling of 81400236 in words is "eighty-one million, four hundred thousand, two hundred thirty-six".