1201001999 has 4 divisors (see below), whose sum is σ = 1201112664. Its totient is φ = 1200891336.

The previous prime is 1201001987. The next prime is 1201002013. The reversal of 1201001999 is 9991001021.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 9991001021 = 19 ⋅525842159.

It is a cyclic number.

It is not a de Polignac number, because 1201001999 - 2⁸ = 1201001743 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 (1201001959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37037 + ... + 61430.

It is an arithmetic number, because the mean of its divisors is an integer number (300278166).

Almost surely, 2^1201001999 is an apocalyptic number.

1201001999 is a deficient number, since it is larger than the sum of its proper divisors (110665).

1201001999 is an equidigital number, since it uses as much as digits as its factorization.

1201001999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110664.

The product of its (nonzero) digits is 1458, while the sum is 32.

The square root of 1201001999 is about 34655.4757433800. The cubic root of 1201001999 is about 1062.9542599039.

The spelling of 1201001999 in words is "one billion, two hundred one million, one thousand, nine hundred ninety-nine".