21692 has 24 divisors (see below), whose sum is σ = 45360. Its totient is φ = 8960.

The previous prime is 21683. The next prime is 21701. The reversal of 21692 is 29612.

It is an interprime number because it is at equal distance from previous prime (21683) and next prime (21701).

It is an alternating number because its digits alternate between even and odd.

It is a nialpdrome in base 15.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 21692.

It is an unprimeable number.

21692 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 734 + ... + 762.

It is an arithmetic number, because the mean of its divisors is an integer number (1890).

2²¹⁶⁹² is an apocalyptic number.

21692 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21692 is an abundant number, since it is smaller than the sum of its proper divisors (23668).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22680).

21692 is a wasteful number, since it uses less digits than its factorization.

21692 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61 (or 59 counting only the distinct ones).

The product of its digits is 216, while the sum is 20.

The square root of 21692 is about 147.2820423541. The cubic root of 21692 is about 27.8890164583.

Adding to 21692 its sum of digits (20), we get a palindrome (21712).

The spelling of 21692 in words is "twenty-one thousand, six hundred ninety-two".