211030021 has 4 divisors (see below), whose sum is σ = 211061772. Its totient is φ = 210998272.

The previous prime is 211029997. The next prime is 211030063. The reversal of 211030021 is 120030112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 193599396 + 17430625 = 13914^2 + 4175^2 .

It is a cyclic number.

It is not a de Polignac number, because 211030021 - 2¹³ = 211021829 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211030091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1666 + ... + 20611.

It is an arithmetic number, because the mean of its divisors is an integer number (52765443).

Almost surely, 2^211030021 is an apocalyptic number.

It is an amenable number.

211030021 is a deficient number, since it is larger than the sum of its proper divisors (31751).

211030021 is an equidigital number, since it uses as much as digits as its factorization.

211030021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31750.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 211030021 is about 14526.8723750159. The cubic root of 211030021 is about 595.3624146155.

Adding to 211030021 its reverse (120030112), we get a palindrome (331060133).

Subtracting from 211030021 its reverse (120030112), we obtain a palindrome (90999909).

It can be divided in two parts, 2110 and 30021, that added together give a triangular number (32131 = T₂₅₃).

The spelling of 211030021 in words is "two hundred eleven million, thirty thousand, twenty-one".