81749442 has 8 divisors (see below), whose sum is σ = 163498896. Its totient is φ = 27249812.

The previous prime is 81749441. The next prime is 81749443. The reversal of 81749442 is 24494718.

It is an interprime number because it is at equal distance from previous prime (81749441) and next prime (81749443).

It is a sphenic number, since it is the product of 3 distinct primes.

81749442 is an admirable number.

It is a super-2 number, since 2×81749442² = 13365942534622728, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81749442.

It is not an unprimeable number, because it can be changed into a prime (81749441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6812448 + ... + 6812459.

It is an arithmetic number, because the mean of its divisors is an integer number (20437362).

Almost surely, 2^81749442 is an apocalyptic number.

81749442 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81749442 is a wasteful number, since it uses less digits than its factorization.

81749442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13624912.

The product of its digits is 64512, while the sum is 39.

The square root of 81749442 is about 9041.5398024894. The cubic root of 81749442 is about 434.0051993119.

It can be divided in two parts, 8174944 and 2, that added together give a triangular number (8174946 = T₄₀₄₃).

The spelling of 81749442 in words is "eighty-one million, seven hundred forty-nine thousand, four hundred forty-two".