210101 has 2 divisors, whose sum is σ = 210102. Its totient is φ = 210100.

The previous prime is 210097. The next prime is 210109. The reversal of 210101 is 101012.

It is a happy number.

210101 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 139876 + 70225 = 374^2 + 265^2 .

It is a cyclic number.

It is not a de Polignac number, because 210101 - 2² = 210097 is a prime.

It is an Ulam number.

It is an alternating number because its digits alternate between even and odd.

210101 is a modest number, since divided by 101 gives 21 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (210109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105050 + 105051.

It is an arithmetic number, because the mean of its divisors is an integer number (105051).

2²¹⁰¹⁰¹ is an apocalyptic number.

It is an amenable number.

210101 is a deficient number, since it is larger than the sum of its proper divisors (1).

210101 is an equidigital number, since it uses as much as digits as its factorization.

210101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2, while the sum is 5.

The square root of 210101 is about 458.3677562831. The cubic root of 210101 is about 59.4487471451.

Adding to 210101 its reverse (101012), we get a palindrome (311113).

Multiplying 210101 by its reverse (101012), we get a palindrome (21222722212).

It can be divided in two parts, 2 and 10101, that multiplied together give a palindrome (20202).

The spelling of 210101 in words is "two hundred ten thousand, one hundred one", and thus it is an iban number.