21611934 has 48 divisors (see below), whose sum is σ = 49423920. Its totient is φ = 7085880.

The previous prime is 21611917. The next prime is 21611939. The reversal of 21611934 is 43911612.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 21611898 and 21611907.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21611939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 354264 + ... + 354324.

It is an arithmetic number, because the mean of its divisors is an integer number (1029665).

Almost surely, 2^21611934 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21611934, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24711960).

21611934 is an abundant number, since it is smaller than the sum of its proper divisors (27811986).

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

21611934 is an frugal number, since it uses more digits than its factorization.

21611934 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96 (or 66 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 21611934 is about 4648.8637321393. The cubic root of 21611934 is about 278.5466101304.

It can be divided in two parts, 216119 and 34, that added together give a triangular number (216153 = T₆₅₇).

The spelling of 21611934 in words is "twenty-one million, six hundred eleven thousand, nine hundred thirty-four".