1000000000021 has 16 divisors (see below), whose sum is σ = 1155178143360. Its totient is φ = 855542433280.

The previous prime is 999999999989. The next prime is 1000000000039. The reversal of 1000000000021 is 1200000000001.

It is a cyclic number.

It is not a de Polignac number, because 1000000000021 - 2⁵ = 999999999989 is a prime.

It is a Duffinian number.

1000000000021 is a modest number, since divided by 21 gives 1 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 1000000000021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1000000000061) 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, 2045625 + ... + 2486881.

It is an arithmetic number, because the mean of its divisors is an integer number (72198633960).

Almost surely, 2^{1000000000021} is an apocalyptic number.

1000000000021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1000000000021 is a deficient number, since it is larger than the sum of its proper divisors (155178143339).

1000000000021 is a wasteful number, since it uses less digits than its factorization.

1000000000021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 453404.

The product of its (nonzero) digits is 2, while the sum is 4.

Adding to 1000000000021 its reverse (1200000000001), we get a palindrome (2200000000022).

The spelling of 1000000000021 in words is "one trillion, twenty-one", and thus it is an aban number and an uban number.