81958253 has 8 divisors (see below), whose sum is σ = 88568088. Its totient is φ = 75392064.

The previous prime is 81958243. The next prime is 81958333. The reversal of 81958253 is 35285918.

It can be written as a sum of positive squares in 4 ways, for example, as 12369289 + 69588964 = 3517^2 + 8342^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 81958253 - 2⁴ = 81958237 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81958253.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81958213) 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, 6950 + ... + 14567.

It is an arithmetic number, because the mean of its divisors is an integer number (11071011).

Almost surely, 2^81958253 is an apocalyptic number.

It is an amenable number.

81958253 is a deficient number, since it is larger than the sum of its proper divisors (6609835).

81958253 is a wasteful number, since it uses less digits than its factorization.

81958253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21823.

The product of its digits is 86400, while the sum is 41.

The square root of 81958253 is about 9053.0797522169. The cubic root of 81958253 is about 434.3744087979.

The spelling of 81958253 in words is "eighty-one million, nine hundred fifty-eight thousand, two hundred fifty-three".