21201211001 has 2 divisors, whose sum is σ = 21201211002. Its totient is φ = 21201211000.

The previous prime is 21201210973. The next prime is 21201211063. The reversal of 21201211001 is 10011210212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21148139776 + 53071225 = 145424^2 + 7285^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201211001 - 2¹⁴ = 21201194617 is a prime.

It is not a weakly prime, because it can be changed into another prime (21201211201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600605500 + 10600605501.

It is an arithmetic number, because the mean of its divisors is an integer number (10600605501).

Almost surely, 2^21201211001 is an apocalyptic number.

It is an amenable number.

21201211001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201211001 is an equidigital number, since it uses as much as digits as its factorization.

21201211001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21201211001 its reverse (10011210212), we get a palindrome (31212421213).

It can be divided in two parts, 2120 and 1211001, that added together give a palindrome (1213121).

The spelling of 21201211001 in words is "twenty-one billion, two hundred one million, two hundred eleven thousand, one".