81066555 has 32 divisors (see below), whose sum is σ = 144529920. Its totient is φ = 43112160.

The previous prime is 81066541. The next prime is 81066563. The reversal of 81066555 is 55566018.

It is not a de Polignac number, because 81066555 - 2¹⁵ = 81033787 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 65674 + ... + 66896.

It is an arithmetic number, because the mean of its divisors is an integer number (4516560).

Almost surely, 2^81066555 is an apocalyptic number.

81066555 is a deficient number, since it is larger than the sum of its proper divisors (63463365).

81066555 is a wasteful number, since it uses less digits than its factorization.

81066555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1728 (or 1722 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

The square root of 81066555 is about 9003.6967407838. The cubic root of 81066555 is about 432.7933434896.

The spelling of 81066555 in words is "eighty-one million, sixty-six thousand, five hundred fifty-five".