201000021 has 16 divisors (see below), whose sum is σ = 278572224. Its totient is φ = 128801664.

The previous prime is 200999983. The next prime is 201000049. The reversal of 201000021 is 120000102.

It is a happy number.

It is not a de Polignac number, because 201000021 - 2¹⁰ = 200998997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 200999973 and 201000009.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201000091) 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, 1696 + ... + 20121.

It is an arithmetic number, because the mean of its divisors is an integer number (17410764).

Almost surely, 2^201000021 is an apocalyptic number.

It is an amenable number.

201000021 is a deficient number, since it is larger than the sum of its proper divisors (77572203).

201000021 is a wasteful number, since it uses less digits than its factorization.

201000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21940.

The product of its (nonzero) digits is 4, while the sum is 6.

The square root of 201000021 is about 14177.4476193707. The cubic root of 201000021 is about 585.7766206652.

Adding to 201000021 its reverse (120000102), we get a palindrome (321000123).

The spelling of 201000021 in words is "two hundred one million, twenty-one", and thus it is an aban number.