1020020999 has 4 divisors (see below), whose sum is σ = 1020435936. Its totient is φ = 1019606064.

The previous prime is 1020020983. The next prime is 1020021127. The reversal of 1020020999 is 9990200201.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9990200201 = 1721 ⋅5804881.

It is a cyclic number.

It is not a de Polignac number, because 1020020999 - 2⁴ = 1020020983 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 (1020020929) 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, 203759 + ... + 208704.

It is an arithmetic number, because the mean of its divisors is an integer number (255108984).

Almost surely, 2^1020020999 is an apocalyptic number.

1020020999 is a deficient number, since it is larger than the sum of its proper divisors (414937).

1020020999 is an equidigital number, since it uses as much as digits as its factorization.

1020020999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414936.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 1020020999 is about 31937.7675957478. The cubic root of 1020020999 is about 1006.6296173788.

The spelling of 1020020999 in words is "one billion, twenty million, twenty thousand, nine hundred ninety-nine".