21820032 has 192 divisors, whose sum is σ = 71285760. Its totient is φ = 6359040.

The previous prime is 21820013. The next prime is 21820033. The reversal of 21820032 is 23002812.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (192).

It is a super-2 number, since 2×21820032² = 952227592962048, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21819987 and 21820014.

It is not an unprimeable number, because it can be changed into a prime (21820033) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 464233 + ... + 464279.

It is an arithmetic number, because the mean of its divisors is an integer number (371280).

Almost surely, 2^21820032 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21820032, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35642880).

21820032 is an abundant number, since it is smaller than the sum of its proper divisors (49465728).

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

21820032 is a wasteful number, since it uses less digits than its factorization.

21820032 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111 (or 96 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21820032 is about 4671.1917109020. The cubic root of 21820032 is about 279.4377834364.

Adding to 21820032 its reverse (23002812), we get a palindrome (44822844).

The spelling of 21820032 in words is "twenty-one million, eight hundred twenty thousand, thirty-two".