1916021000021 has 2 divisors, whose sum is σ = 1916021000022. Its totient is φ = 1916021000020.

The previous prime is 1916021000011. The next prime is 1916021000063. The reversal of 1916021000021 is 1200001206191.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1043452035025 + 872568964996 = 1021495^2 + 934114^2 .

It is a cyclic number.

It is not a de Polignac number, because 1916021000021 - 2³⁰ = 1914947258197 is a prime.

It is a super-2 number, since 2×1916021000021² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1916021000011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 958010500010 + 958010500011.

It is an arithmetic number, because the mean of its divisors is an integer number (958010500011).

Almost surely, 2^{1916021000021} is an apocalyptic number.

It is an amenable number.

1916021000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1916021000021 is an equidigital number, since it uses as much as digits as its factorization.

1916021000021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 23.

The spelling of 1916021000021 in words is "one trillion, nine hundred sixteen billion, twenty-one million, twenty-one", and thus it is an aban number.