81670653 has 8 divisors (see below), whose sum is σ = 120993600. Its totient is φ = 54447084.

The previous prime is 81670619. The next prime is 81670663. The reversal of 81670653 is 35607618.

It is not a de Polignac number, because 81670653 - 2¹⁷ = 81539581 is a prime.

It is a super-2 number, since 2×81670653² = 13340191122892818, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81670663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1512393 + ... + 1512446.

It is an arithmetic number, because the mean of its divisors is an integer number (15124200).

Almost surely, 2^81670653 is an apocalyptic number.

It is an amenable number.

81670653 is a deficient number, since it is larger than the sum of its proper divisors (39322947).

81670653 is a wasteful number, since it uses less digits than its factorization.

81670653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3024848 (or 3024842 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 81670653 is about 9037.1816956394. The cubic root of 81670653 is about 433.8657250591.

The spelling of 81670653 in words is "eighty-one million, six hundred seventy thousand, six hundred fifty-three".