81953783 has 8 divisors (see below), whose sum is σ = 86718000. Its totient is φ = 77234688.

The previous prime is 81953771. The next prime is 81953819. The reversal of 81953783 is 38735918.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81953783 is a prime.

It is a super-2 number, since 2×81953783² = 13432845096022178, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81953713) 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, 7508 + ... + 14841.

It is an arithmetic number, because the mean of its divisors is an integer number (10839750).

Almost surely, 2^81953783 is an apocalyptic number.

81953783 is a deficient number, since it is larger than the sum of its proper divisors (4764217).

81953783 is a wasteful number, since it uses less digits than its factorization.

81953783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22561.

The product of its digits is 181440, while the sum is 44.

The square root of 81953783 is about 9052.8328715381. The cubic root of 81953783 is about 434.3665117331.

The spelling of 81953783 in words is "eighty-one million, nine hundred fifty-three thousand, seven hundred eighty-three".