21851683547 has 2 divisors, whose sum is σ = 21851683548. Its totient is φ = 21851683546.

The previous prime is 21851683537. The next prime is 21851683573. The reversal of 21851683547 is 74538615812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21851683547 - 2²⁸ = 21583248091 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21851683495 and 21851683504.

It is not a weakly prime, because it can be changed into another prime (21851683507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10925841773 + 10925841774.

It is an arithmetic number, because the mean of its divisors is an integer number (10925841774).

Almost surely, 2^21851683547 is an apocalyptic number.

21851683547 is a deficient number, since it is larger than the sum of its proper divisors (1).

21851683547 is an equidigital number, since it uses as much as digits as its factorization.

21851683547 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1612800, while the sum is 50.

The spelling of 21851683547 in words is "twenty-one billion, eight hundred fifty-one million, six hundred eighty-three thousand, five hundred forty-seven".