21609834 has 16 divisors (see below), whose sum is σ = 45099072. Its totient is φ = 6890048.

The previous prime is 21609817. The next prime is 21609851. The reversal of 21609834 is 43890612.

It is an interprime number because it is at equal distance from previous prime (21609817) and next prime (21609851).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21609795 and 21609804.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78159 + ... + 78434.

It is an arithmetic number, because the mean of its divisors is an integer number (2818692).

Almost surely, 2^21609834 is an apocalyptic number.

21609834 is an abundant number, since it is smaller than the sum of its proper divisors (23489238).

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

21609834 is a wasteful number, since it uses less digits than its factorization.

21609834 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156621.

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 21609834 is about 4648.6378650095. The cubic root of 21609834 is about 278.5375878494.

The spelling of 21609834 in words is "twenty-one million, six hundred nine thousand, eight hundred thirty-four".