999201231221 has 4 divisors (see below), whose sum is σ = 1057977774252. Its totient is φ = 940424688192.

The previous prime is 999201231209. The next prime is 999201231241. The reversal of 999201231221 is 122132102999.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 571557168196 + 427644063025 = 756014^2 + 653945^2 .

It is a cyclic number.

It is not a de Polignac number, because 999201231221 - 2¹⁰ = 999201230197 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 (999201231241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29388271490 + ... + 29388271523.

It is an arithmetic number, because the mean of its divisors is an integer number (264494443563).

Almost surely, 2^999201231221 is an apocalyptic number.

It is an amenable number.

999201231221 is a deficient number, since it is larger than the sum of its proper divisors (58776543031).

999201231221 is a wasteful number, since it uses less digits than its factorization.

999201231221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58776543030.

The product of its (nonzero) digits is 34992, while the sum is 41.

The spelling of 999201231221 in words is "nine hundred ninety-nine billion, two hundred one million, two hundred thirty-one thousand, two hundred twenty-one".