81887736 has 32 divisors (see below), whose sum is σ = 233965440. Its totient is φ = 23396448.

The previous prime is 81887723. The next prime is 81887737. The reversal of 81887736 is 63778818.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81887737) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 243546 + ... + 243881.

It is an arithmetic number, because the mean of its divisors is an integer number (7311420).

Almost surely, 2^81887736 is an apocalyptic number.

It is an amenable number.

81887736 is an abundant number, since it is smaller than the sum of its proper divisors (152077704).

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

81887736 is a wasteful number, since it uses less digits than its factorization.

81887736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 487443 (or 487439 counting only the distinct ones).

The product of its digits is 451584, while the sum is 48.

The square root of 81887736 is about 9049.1842726292. The cubic root of 81887736 is about 434.2497942607.

The spelling of 81887736 in words is "eighty-one million, eight hundred eighty-seven thousand, seven hundred thirty-six".