81394470 has 160 divisors (see below), whose sum is σ = 242751168. Its totient is φ = 19464192.

The previous prime is 81394457. The next prime is 81394507. The reversal of 81394470 is 7449318.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 316582 + ... + 316838.

Almost surely, 2^81394470 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81394470, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121375584).

81394470 is an abundant number, since it is smaller than the sum of its proper divisors (161356698).

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

81394470 is a wasteful number, since it uses less digits than its factorization.

81394470 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316 (or 307 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 81394470 is about 9021.8883832599. Note that the first 3 decimals coincide. The cubic root of 81394470 is about 433.3761095182.

The spelling of 81394470 in words is "eighty-one million, three hundred ninety-four thousand, four hundred seventy".