201021021 has 28 divisors (see below), whose sum is σ = 307858752. Its totient is φ = 131140296.

The previous prime is 201020987. The next prime is 201021043. The reversal of 201021021 is 120120102.

It is not a de Polignac number, because 201021021 - 2¹⁴ = 201004637 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 201020994 and 201021012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201021071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 31330 + ... + 37196.

Almost surely, 2^201021021 is an apocalyptic number.

It is an amenable number.

201021021 is a deficient number, since it is larger than the sum of its proper divisors (106837731).

201021021 is an frugal number, since it uses more digits than its factorization.

201021021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5932 (or 5917 counting only the distinct ones).

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

The square root of 201021021 is about 14178.1882128853. The cubic root of 201021021 is about 585.7970201335.

Adding to 201021021 its reverse (120120102), we get a palindrome (321141123).

The spelling of 201021021 in words is "two hundred one million, twenty-one thousand, twenty-one".