81857742 has 8 divisors (see below), whose sum is σ = 163715496. Its totient is φ = 27285912.

The previous prime is 81857731. The next prime is 81857753. The reversal of 81857742 is 24775818.

It is an interprime number because it is at equal distance from previous prime (81857731) and next prime (81857753).

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

81857742 is an admirable number.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 81857694 and 81857703.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6821473 + ... + 6821484.

It is an arithmetic number, because the mean of its divisors is an integer number (20464437).

Almost surely, 2^81857742 is an apocalyptic number.

81857742 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.

81857742 is a wasteful number, since it uses less digits than its factorization.

81857742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13642962.

The product of its digits is 125440, while the sum is 42.

The square root of 81857742 is about 9047.5268443923. The cubic root of 81857742 is about 434.1967684982.

The spelling of 81857742 in words is "eighty-one million, eight hundred fifty-seven thousand, seven hundred forty-two".