210221001 has 27 divisors (see below), whose sum is σ = 317086861. Its totient is φ = 139364388.

The previous prime is 210220999. The next prime is 210221003. The reversal of 210221001 is 100122012.

The square root of 210221001 is 14499.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (210220999) and next prime (210221003).

It is a tau number, because it is divible by the number of its divisors (27).

It is not a de Polignac number, because 210221001 - 2¹ = 210220999 is a prime.

It is a super-2 number, since 2×210221001² = 88385738522884002, which contains 22 as substring.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (210221003) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1174330 + ... + 1174508.

Almost surely, 2^210221001 is an apocalyptic number.

210221001 is the 14499-th square number.

210221001 is the 7250-th centered octagonal number.

It is an amenable number.

210221001 is a deficient number, since it is larger than the sum of its proper divisors (106865860).

210221001 is an frugal number, since it uses more digits than its factorization.

210221001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382 (or 182 counting only the distinct ones).

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

The cubic root of 210221001 is about 594.6006321264.

Adding to 210221001 its reverse (100122012), we get a palindrome (310343013).

The spelling of 210221001 in words is "two hundred ten million, two hundred twenty-one thousand, one".