999726121 has 4 divisors (see below), whose sum is σ = 1018588932. Its totient is φ = 980863312.

The previous prime is 999726103. The next prime is 999726197. The reversal of 999726121 is 121627999.

It is a happy number.

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 655104025 + 344622096 = 25595^2 + 18564^2 .

It is a cyclic number.

It is not a de Polignac number, because 999726121 - 2¹¹ = 999724073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (999723121) 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, 9431326 + ... + 9431431.

It is an arithmetic number, because the mean of its divisors is an integer number (254647233).

Almost surely, 2^999726121 is an apocalyptic number.

It is an amenable number.

999726121 is a deficient number, since it is larger than the sum of its proper divisors (18862811).

999726121 is a wasteful number, since it uses less digits than its factorization.

999726121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18862810.

The product of its digits is 122472, while the sum is 46.

The square root of 999726121 is about 31618.4458979248. The cubic root of 999726121 is about 999.9086986643.

The spelling of 999726121 in words is "nine hundred ninety-nine million, seven hundred twenty-six thousand, one hundred twenty-one".