21021111029 has 2 divisors, whose sum is σ = 21021111030. Its totient is φ = 21021111028.

The previous prime is 21021110989. The next prime is 21021111049. The reversal of 21021111029 is 92011112012.

It is an a-pointer prime, because the next prime (21021111049) can be obtained adding 21021111029 to its sum of digits (20).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17102100625 + 3919010404 = 130775^2 + 62602^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21021111029 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21021111029.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021111049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510555514 + 10510555515.

It is an arithmetic number, because the mean of its divisors is an integer number (10510555515).

Almost surely, 2^21021111029 is an apocalyptic number.

It is an amenable number.

21021111029 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021111029 is an equidigital number, since it uses as much as digits as its factorization.

21021111029 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 21021111029 in words is "twenty-one billion, twenty-one million, one hundred eleven thousand, twenty-nine".