1200021999 has 16 divisors (see below), whose sum is σ = 1792663680. Its totient is φ = 707628960.

The previous prime is 1200021983. The next prime is 1200022037. The reversal of 1200021999 is 9991200021.

It is not a de Polignac number, because 1200021999 - 2⁴ = 1200021983 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1200020999) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 490189 + ... + 492630.

It is an arithmetic number, because the mean of its divisors is an integer number (112041480).

Almost surely, 2^1200021999 is an apocalyptic number.

1200021999 is a deficient number, since it is larger than the sum of its proper divisors (592641681).

1200021999 is a wasteful number, since it uses less digits than its factorization.

1200021999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 982870.

The product of its (nonzero) digits is 2916, while the sum is 33.

The square root of 1200021999 is about 34641.3336781366. Note that the first 3 decimals coincide. The cubic root of 1200021999 is about 1062.6650628723.

The spelling of 1200021999 in words is "one billion, two hundred million, twenty-one thousand, nine hundred ninety-nine".