81740887 has 4 divisors (see below), whose sum is σ = 82197720. Its totient is φ = 81284056.

The previous prime is 81740861. The next prime is 81740891. The reversal of 81740887 is 78804718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78804718 = 2 ⋅39402359.

It is a cyclic number.

It is not a de Polignac number, because 81740887 - 2⁷ = 81740759 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81740837) 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, 228148 + ... + 228505.

It is an arithmetic number, because the mean of its divisors is an integer number (20549430).

Almost surely, 2^81740887 is an apocalyptic number.

81740887 is a deficient number, since it is larger than the sum of its proper divisors (456833).

81740887 is a wasteful number, since it uses less digits than its factorization.

81740887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 456832.

The product of its (nonzero) digits is 100352, while the sum is 43.

The square root of 81740887 is about 9041.0666959159. The cubic root of 81740887 is about 433.9900593758.

The spelling of 81740887 in words is "eighty-one million, seven hundred forty thousand, eight hundred eighty-seven".