21122001 has 12 divisors (see below), whose sum is σ = 30551040. Its totient is φ = 14062200.

The previous prime is 21121999. The next prime is 21122009. The reversal of 21122001 is 10022112.

It is not a de Polignac number, because 21122001 - 2¹ = 21121999 is a prime.

It is a super-2 number, since 2×21122001² = 892277852488002, which contains 22 as substring.

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

It is a Curzon number.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9340 + ... + 11378.

It is an arithmetic number, because the mean of its divisors is an integer number (2545920).

Almost surely, 2^21122001 is an apocalyptic number.

It is an amenable number.

21122001 is a deficient number, since it is larger than the sum of its proper divisors (9429039).

21122001 is a wasteful number, since it uses less digits than its factorization.

21122001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3196 (or 3193 counting only the distinct ones).

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

The square root of 21122001 is about 4595.8678179425. The cubic root of 21122001 is about 276.4256585693.

Adding to 21122001 its reverse (10022112), we get a palindrome (31144113).

The spelling of 21122001 in words is "twenty-one million, one hundred twenty-two thousand, one".