21305934 has 48 divisors (see below), whose sum is σ = 50358672. Its totient is φ = 6470784.

The previous prime is 21305929. The next prime is 21305939. The reversal of 21305934 is 43950312.

It is an interprime number because it is at equal distance from previous prime (21305929) and next prime (21305939).

It is a super-2 number, since 2×21305934² = 907885647224712, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21305898 and 21305907.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21305939) 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, 18874 + ... + 19970.

It is an arithmetic number, because the mean of its divisors is an integer number (1049139).

Almost surely, 2^21305934 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21305934, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25179336).

21305934 is an abundant number, since it is smaller than the sum of its proper divisors (29052738).

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

21305934 is a wasteful number, since it uses less digits than its factorization.

21305934 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1201 (or 1198 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 21305934 is about 4615.8351357040. The cubic root of 21305934 is about 277.2257236424.

The spelling of 21305934 in words is "twenty-one million, three hundred five thousand, nine hundred thirty-four".