21854653991 has 2 divisors, whose sum is σ = 21854653992. Its totient is φ = 21854653990.

The previous prime is 21854653927. The next prime is 21854654057. The reversal of 21854653991 is 19935645812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21854653991 - 2⁶ = 21854653927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21854653591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10927326995 + 10927326996.

It is an arithmetic number, because the mean of its divisors is an integer number (10927326996).

Almost surely, 2^21854653991 is an apocalyptic number.

21854653991 is a deficient number, since it is larger than the sum of its proper divisors (1).

21854653991 is an equidigital number, since it uses as much as digits as its factorization.

21854653991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2332800, while the sum is 53.

The spelling of 21854653991 in words is "twenty-one billion, eight hundred fifty-four million, six hundred fifty-three thousand, nine hundred ninety-one".