81223773201 has 24 divisors (see below), whose sum is σ = 117697687016. Its totient is φ = 53976637440.

The previous prime is 81223773143. The next prime is 81223773229. The reversal of 81223773201 is 10237732218.

81223773201 is a `hidden beast` number, since 81 + 2 + 2 + 377 + 3 + 201 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2698283025 + 78525490176 = 51945^2 + 280224^2 .

It is not a de Polignac number, because 81223773201 - 2¹³ = 81223765009 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81223773601) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3635601 + ... + 3657873.

Almost surely, 2^81223773201 is an apocalyptic number.

It is an amenable number.

81223773201 is a deficient number, since it is larger than the sum of its proper divisors (36473913815).

81223773201 is a wasteful number, since it uses less digits than its factorization.

81223773201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23553 (or 23550 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 36.

The spelling of 81223773201 in words is "eighty-one billion, two hundred twenty-three million, seven hundred seventy-three thousand, two hundred one".