21213033161 has 2 divisors, whose sum is σ = 21213033162. Its totient is φ = 21213033160.

The previous prime is 21213033137. The next prime is 21213033167. The reversal of 21213033161 is 16133031212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17336725561 + 3876307600 = 131669^2 + 62260^2 .

It is a cyclic number.

It is not a de Polignac number, because 21213033161 - 2⁶ = 21213033097 is a prime.

It is not a weakly prime, because it can be changed into another prime (21213033167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606516580 + 10606516581.

It is an arithmetic number, because the mean of its divisors is an integer number (10606516581).

Almost surely, 2^21213033161 is an apocalyptic number.

It is an amenable number.

21213033161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213033161 is an equidigital number, since it uses as much as digits as its factorization.

21213033161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 23.

Adding to 21213033161 its reverse (16133031212), we get a palindrome (37346064373).

The spelling of 21213033161 in words is "twenty-one billion, two hundred thirteen million, thirty-three thousand, one hundred sixty-one".