81029740 has 48 divisors (see below), whose sum is σ = 186792480. Its totient is φ = 29281280.

The previous prime is 81029723. The next prime is 81029749. The reversal of 81029740 is 4792018.

It is not an unprimeable number, because it can be changed into a prime (81029749) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 36996 + ... + 39124.

It is an arithmetic number, because the mean of its divisors is an integer number (3891510).

Almost surely, 2^81029740 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81029740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93396240).

81029740 is an abundant number, since it is smaller than the sum of its proper divisors (105762740).

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

81029740 is a wasteful number, since it uses less digits than its factorization.

81029740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2322 (or 2320 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 81029740 is about 9001.6520705924. The cubic root of 81029740 is about 432.7278183192.

The spelling of 81029740 in words is "eighty-one million, twenty-nine thousand, seven hundred forty".