81445380 has 24 divisors (see below), whose sum is σ = 228047232. Its totient is φ = 21718752.

The previous prime is 81445379. The next prime is 81445387. The reversal of 81445380 is 8354418.

It is not an unprimeable number, because it can be changed into a prime (81445387) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 678652 + ... + 678771.

It is an arithmetic number, because the mean of its divisors is an integer number (9501968).

Almost surely, 2^81445380 is an apocalyptic number.

It is an amenable number.

81445380 is an abundant number, since it is smaller than the sum of its proper divisors (146601852).

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

81445380 is a wasteful number, since it uses less digits than its factorization.

81445380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1357435 (or 1357433 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 33.

The square root of 81445380 is about 9024.7094136044. The cubic root of 81445380 is about 433.4664456281.

Adding to 81445380 its reverse (8354418), we get a palindrome (89799798).

The spelling of 81445380 in words is "eighty-one million, four hundred forty-five thousand, three hundred eighty".