21188634 has 32 divisors (see below), whose sum is σ = 43600896. Its totient is φ = 6861360.

The previous prime is 21188633. The next prime is 21188639. The reversal of 21188634 is 43688112.

It is a junction number, because it is equal to n+sod(n) for n = 21188595 and 21188604.

It is not an unprimeable number, because it can be changed into a prime (21188633) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63849 + ... + 64179.

It is an arithmetic number, because the mean of its divisors is an integer number (1362528).

Almost surely, 2^21188634 is an apocalyptic number.

21188634 is an abundant number, since it is smaller than the sum of its proper divisors (22412262).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21188634 is a wasteful number, since it uses less digits than its factorization.

21188634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610.

The product of its digits is 9216, while the sum is 33.

The square root of 21188634 is about 4603.1113390836. Note that the first 3 decimals coincide. The cubic root of 21188634 is about 276.7160309329.

The spelling of 21188634 in words is "twenty-one million, one hundred eighty-eight thousand, six hundred thirty-four".