81066653 has 4 divisors (see below), whose sum is σ = 82951968. Its totient is φ = 79181340.

The previous prime is 81066637. The next prime is 81066691. The reversal of 81066653 is 35666018.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 35666018 = 2 ⋅17833009.

It is a cyclic number.

It is not a de Polignac number, because 81066653 - 2⁴ = 81066637 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 (81060653) 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, 942593 + ... + 942678.

It is an arithmetic number, because the mean of its divisors is an integer number (20737992).

Almost surely, 2^81066653 is an apocalyptic number.

It is an amenable number.

81066653 is a deficient number, since it is larger than the sum of its proper divisors (1885315).

81066653 is a wasteful number, since it uses less digits than its factorization.

81066653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1885314.

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 81066653 is about 9003.7021829912. The cubic root of 81066653 is about 432.7935178884.

The spelling of 81066653 in words is "eighty-one million, sixty-six thousand, six hundred fifty-three".