81210845 has 16 divisors (see below), whose sum is σ = 104328000. Its totient is φ = 60501888.

The previous prime is 81210823. The next prime is 81210881. The reversal of 81210845 is 54801218.

It is a cyclic number.

It is not a de Polignac number, because 81210845 - 2⁶ = 81210781 is a prime.

It is a super-2 number, since 2×81210845² = 13190402691228050, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 1640 + ... + 12849.

It is an arithmetic number, because the mean of its divisors is an integer number (6520500).

Almost surely, 2^81210845 is an apocalyptic number.

It is an amenable number.

81210845 is a deficient number, since it is larger than the sum of its proper divisors (23117155).

81210845 is a wasteful number, since it uses less digits than its factorization.

81210845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14572.

The product of its (nonzero) digits is 2560, while the sum is 29.

The square root of 81210845 is about 9011.7059983113. The cubic root of 81210845 is about 433.0499669432.

The spelling of 81210845 in words is "eighty-one million, two hundred ten thousand, eight hundred forty-five".