81643155293 has 8 divisors (see below), whose sum is σ = 96523927680. Its totient is φ = 67566749040.

The previous prime is 81643155281. The next prime is 81643155337. The reversal of 81643155293 is 39255134618.

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

It is not a de Polignac number, because 81643155293 - 2⁴ = 81643155277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81643155203) 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, 201091313 + ... + 201091718.

It is an arithmetic number, because the mean of its divisors is an integer number (12065490960).

Almost surely, 2^81643155293 is an apocalyptic number.

It is an amenable number.

81643155293 is a deficient number, since it is larger than the sum of its proper divisors (14880772387).

81643155293 is a wasteful number, since it uses less digits than its factorization.

81643155293 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 402183067.

The product of its digits is 777600, while the sum is 47.

The spelling of 81643155293 in words is "eighty-one billion, six hundred forty-three million, one hundred fifty-five thousand, two hundred ninety-three".