1002012021 has 12 divisors (see below), whose sum is σ = 1455719148. Its totient is φ = 664145664.

The previous prime is 1002012017. The next prime is 1002012071. The reversal of 1002012021 is 1202102001.

It can be written as a sum of positive squares in 2 ways, for example, as 695376900 + 306635121 = 26370^2 + 17511^2 .

It is not a de Polignac number, because 1002012021 - 2² = 1002012017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 1002011994 and 1002012012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1002012071) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 320220 + ... + 323333.

It is an arithmetic number, because the mean of its divisors is an integer number (121309929).

Almost surely, 2^1002012021 is an apocalyptic number.

It is an amenable number.

1002012021 is a deficient number, since it is larger than the sum of its proper divisors (453707127).

1002012021 is a wasteful number, since it uses less digits than its factorization.

1002012021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 643732 (or 643729 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1002012021 is about 31654.5734610340. The cubic root of 1002012021 is about 1000.6702243656.

Adding to 1002012021 its reverse (1202102001), we get a palindrome (2204114022).

The spelling of 1002012021 in words is "one billion, two million, twelve thousand, twenty-one".