81379494 has 72 divisors (see below), whose sum is σ = 206472240. Its totient is φ = 23164848.

The previous prime is 81379483. The next prime is 81379511. The reversal of 81379494 is 49497318.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 302392 + ... + 302660.

It is an arithmetic number, because the mean of its divisors is an integer number (2867670).

Almost surely, 2^81379494 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81379494, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103236120).

81379494 is an abundant number, since it is smaller than the sum of its proper divisors (125092746).

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

81379494 is an equidigital number, since it uses as much as digits as its factorization.

81379494 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312 (or 281 counting only the distinct ones).

The product of its digits is 217728, while the sum is 45.

The square root of 81379494 is about 9021.0583636290. The cubic root of 81379494 is about 433.3495285203.

The spelling of 81379494 in words is "eighty-one million, three hundred seventy-nine thousand, four hundred ninety-four".