81554987 has 8 divisors (see below), whose sum is σ = 86497440. Its totient is φ = 76728960.

The previous prime is 81554959. The next prime is 81555007. The reversal of 81554987 is 78945518.

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

It is a cyclic number.

It is not a de Polignac number, because 81554987 - 2⁶ = 81554923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81554927) 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, 27662 + ... + 30467.

It is an arithmetic number, because the mean of its divisors is an integer number (10812180).

Almost surely, 2^81554987 is an apocalyptic number.

81554987 is a deficient number, since it is larger than the sum of its proper divisors (4942453).

81554987 is a wasteful number, since it uses less digits than its factorization.

81554987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58213.

The product of its digits is 403200, while the sum is 47.

The square root of 81554987 is about 9030.7799773884. The cubic root of 81554987 is about 433.6608076232.

The spelling of 81554987 in words is "eighty-one million, five hundred fifty-four thousand, nine hundred eighty-seven".