21385611 has 24 divisors (see below), whose sum is σ = 33983040. Its totient is φ = 12877056.

The previous prime is 21385603. The next prime is 21385627. The reversal of 21385611 is 11658312.

It is not a de Polignac number, because 21385611 - 2³ = 21385603 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21385681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3555 + ... + 7443.

It is an arithmetic number, because the mean of its divisors is an integer number (1415960).

Almost surely, 2^21385611 is an apocalyptic number.

21385611 is a deficient number, since it is larger than the sum of its proper divisors (12597429).

21385611 is a wasteful number, since it uses less digits than its factorization.

21385611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3955 (or 3952 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 21385611 is about 4624.4579141776. The cubic root of 21385611 is about 277.5708706254.

The spelling of 21385611 in words is "twenty-one million, three hundred eighty-five thousand, six hundred eleven".