1021001000021 has 16 divisors (see below), whose sum is σ = 1071426559104. Its totient is φ = 971084097984.

The previous prime is 1021001000017. The next prime is 1021001000027. The reversal of 1021001000021 is 1200001001201.

It is a cyclic number.

It is not a de Polignac number, because 1021001000021 - 2² = 1021001000017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1021000999972 and 1021001000008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021001000027) 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, 7787210 + ... + 7917236.

It is an arithmetic number, because the mean of its divisors is an integer number (66964159944).

Almost surely, 2^{1021001000021} is an apocalyptic number.

It is an amenable number.

1021001000021 is a deficient number, since it is larger than the sum of its proper divisors (50425559083).

1021001000021 is a wasteful number, since it uses less digits than its factorization.

1021001000021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131980.

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 1021001000021 its reverse (1200001001201), we get a palindrome (2221002001222).

The spelling of 1021001000021 in words is "one trillion, twenty-one billion, one million, twenty-one", and thus it is an aban number and an uban number.