21451826991005 has 16 divisors (see below), whose sum is σ = 26473995599664. Its totient is φ = 16674858339840.

The previous prime is 21451826990981. The next prime is 21451826991011. The reversal of 21451826991005 is 50019962815412.

It can be written as a sum of positive squares in 8 ways, for example, as 1164027367801 + 20287799623204 = 1078901^2 + 4504198^2 .

It is not a de Polignac number, because 21451826991005 - 2³⁴ = 21434647121821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 78961136 + ... + 79232345.

It is an arithmetic number, because the mean of its divisors is an integer number (1654624724979).

Almost surely, 2^{21451826991005} is an apocalyptic number.

It is an amenable number.

21451826991005 is a deficient number, since it is larger than the sum of its proper divisors (5022168608659).

21451826991005 is a wasteful number, since it uses less digits than its factorization.

21451826991005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158194256.

The product of its (nonzero) digits is 1555200, while the sum is 53.

The spelling of 21451826991005 in words is "twenty-one trillion, four hundred fifty-one billion, eight hundred twenty-six million, nine hundred ninety-one thousand, five".