21691692 has 144 divisors (see below), whose sum is σ = 66729600. Its totient is φ = 6026400.

The previous prime is 21691633. The next prime is 21691693. The reversal of 21691692 is 29619612.

It is a super-3 number, since 3×21691692³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21691693) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 699717 + ... + 699747.

It is an arithmetic number, because the mean of its divisors is an integer number (463400).

Almost surely, 2^21691692 is an apocalyptic number.

21691692 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21691692, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33364800).

21691692 is an abundant number, since it is smaller than the sum of its proper divisors (45037908).

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

21691692 is a wasteful number, since it uses less digits than its factorization.

21691692 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105 (or 66 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 21691692 is about 4657.4340575042. The cubic root of 21691692 is about 278.8888446097. Note that the first 4 decimals are identical.

The spelling of 21691692 in words is "twenty-one million, six hundred ninety-one thousand, six hundred ninety-two".