21001122 has 12 divisors (see below), whose sum is σ = 45502470. Its totient is φ = 7000368.

The previous prime is 21001121. The next prime is 21001153. The reversal of 21001122 is 22110012.

It can be written as a sum of positive squares in only one way, i.e., 15139881 + 5861241 = 3891^2 + 2421^2 .

It is a super-3 number, since 3×21001122³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (21001121) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 583347 + ... + 583382.

Almost surely, 2^21001122 is an apocalyptic number.

21001122 is an abundant number, since it is smaller than the sum of its proper divisors (24501348).

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

21001122 is a wasteful number, since it uses less digits than its factorization.

21001122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1166737 (or 1166734 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21001122 is about 4582.6981135571. The cubic root of 21001122 is about 275.8973310632.

Adding to 21001122 its reverse (22110012), we get a palindrome (43111134).

The spelling of 21001122 in words is "twenty-one million, one thousand, one hundred twenty-two".