21906346524787 has 2 divisors, whose sum is σ = 21906346524788. Its totient is φ = 21906346524786.

The previous prime is 21906346524743. The next prime is 21906346524857. The reversal of 21906346524787 is 78742564360912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21906346524787 - 2¹⁹ = 21906346000499 is a prime.

It is not a weakly prime, because it can be changed into another prime (21906346524187) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10953173262393 + 10953173262394.

It is an arithmetic number, because the mean of its divisors is an integer number (10953173262394).

It is a 2-persistent number, because it is pandigital, and so is 2⋅21906346524787 = 43812693049574, but 3⋅21906346524787 = 65719039574361 is not.

Almost surely, 2^{21906346524787} is an apocalyptic number.

21906346524787 is a deficient number, since it is larger than the sum of its proper divisors (1).

21906346524787 is an equidigital number, since it uses as much as digits as its factorization.

21906346524787 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 121927680, while the sum is 64.

The spelling of 21906346524787 in words is "twenty-one trillion, nine hundred six billion, three hundred forty-six million, five hundred twenty-four thousand, seven hundred eighty-seven".