81651123285 has 8 divisors (see below), whose sum is σ = 130641797280. Its totient is φ = 43547265744.

The previous prime is 81651123283. The next prime is 81651123289. The reversal of 81651123285 is 58232115618.

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

It is not a de Polignac number, because 81651123285 - 2¹ = 81651123283 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81651123283) 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, 2721704095 + ... + 2721704124.

It is an arithmetic number, because the mean of its divisors is an integer number (16330224660).

Almost surely, 2^81651123285 is an apocalyptic number.

It is an amenable number.

81651123285 is a deficient number, since it is larger than the sum of its proper divisors (48990673995).

81651123285 is a wasteful number, since it uses less digits than its factorization.

81651123285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5443408227.

The product of its digits is 115200, while the sum is 42.

The spelling of 81651123285 in words is "eighty-one billion, six hundred fifty-one million, one hundred twenty-three thousand, two hundred eighty-five".