81429390 has 96 divisors (see below), whose sum is σ = 250361280. Its totient is φ = 17966592.

The previous prime is 81429379. The next prime is 81429409. The reversal of 81429390 is 9392418.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 16042 + ... + 20498.

It is an arithmetic number, because the mean of its divisors is an integer number (2607930).

Almost surely, 2^81429390 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81429390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125180640).

81429390 is an abundant number, since it is smaller than the sum of its proper divisors (168931890).

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

81429390 is a wasteful number, since it uses less digits than its factorization.

81429390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4506 (or 4503 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 81429390 is about 9023.8234690180. The cubic root of 81429390 is about 433.4380765866.

The spelling of 81429390 in words is "eighty-one million, four hundred twenty-nine thousand, three hundred ninety".