1020001999 has 16 divisors (see below), whose sum is σ = 1075737600. Its totient is φ = 965273760.

The previous prime is 1020001991. The next prime is 1020002017. The reversal of 1020001999 is 9991000201.

It is a cyclic number.

It is not a de Polignac number, because 1020001999 - 2³ = 1020001991 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1020001999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1020001991) 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, 1257304 + ... + 1258114.

It is an arithmetic number, because the mean of its divisors is an integer number (67233600).

Almost surely, 2^1020001999 is an apocalyptic number.

1020001999 is a deficient number, since it is larger than the sum of its proper divisors (55735601).

1020001999 is a wasteful number, since it uses less digits than its factorization.

1020001999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1350.

The product of its (nonzero) digits is 1458, while the sum is 31.

The square root of 1020001999 is about 31937.4701408862. The cubic root of 1020001999 is about 1006.6233671541.

The spelling of 1020001999 in words is "one billion, twenty million, one thousand, nine hundred ninety-nine".