81744987 has 16 divisors (see below), whose sum is σ = 110816640. Its totient is φ = 53592000.

The previous prime is 81744983. The next prime is 81745003. The reversal of 81744987 is 78944718.

It is not a de Polignac number, because 81744987 - 2² = 81744983 is a prime.

It is a super-3 number, since 3×81744987³ (a number of 25 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (81744983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55612 + ... + 57062.

It is an arithmetic number, because the mean of its divisors is an integer number (6926040).

Almost surely, 2^81744987 is an apocalyptic number.

81744987 is a deficient number, since it is larger than the sum of its proper divisors (29071653).

81744987 is a wasteful number, since it uses less digits than its factorization.

81744987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1754.

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

The square root of 81744987 is about 9041.2934362291. The cubic root of 81744987 is about 433.9973153507.

The spelling of 81744987 in words is "eighty-one million, seven hundred forty-four thousand, nine hundred eighty-seven".