21122000 has 80 divisors (see below), whose sum is σ = 52228800. Its totient is φ = 8259200.

The previous prime is 21121999. The next prime is 21122009. The reversal of 21122000 is 22112.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×21122000² = 892277768000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122009) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 117911 + ... + 118089.

It is an arithmetic number, because the mean of its divisors is an integer number (652860).

Almost surely, 2^21122000 is an apocalyptic number.

21122000 is a gapful number since it is divisible by the number (20) 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 21122000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26114400).

21122000 is an abundant number, since it is smaller than the sum of its proper divisors (31106800).

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

21122000 is a wasteful number, since it uses less digits than its factorization.

21122000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261 (or 245 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 21122000 is about 4595.8677091492. The cubic root of 21122000 is about 276.4256542069.

Adding to 21122000 its reverse (22112), we get a palindrome (21144112).

The spelling of 21122000 in words is "twenty-one million, one hundred twenty-two thousand".