21111021013 has 2 divisors, whose sum is σ = 21111021014. Its totient is φ = 21111021012.

The previous prime is 21111020977. The next prime is 21111021023. The reversal of 21111021013 is 31012011112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12134784964 + 8976236049 = 110158^2 + 94743^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111021013 - 2¹³ = 21111012821 is a prime.

It is a super-2 number, since 2×21111021013² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21111020984 and 21111021002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111021023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555510506 + 10555510507.

It is an arithmetic number, because the mean of its divisors is an integer number (10555510507).

Almost surely, 2^21111021013 is an apocalyptic number.

It is an amenable number.

21111021013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111021013 is an equidigital number, since it uses as much as digits as its factorization.

21111021013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12, while the sum is 13.

Adding to 21111021013 its reverse (31012011112), we get a palindrome (52123032125).

Subtracting 21111021013 from its reverse (31012011112), we obtain a palindrome (9900990099).

The spelling of 21111021013 in words is "twenty-one billion, one hundred eleven million, twenty-one thousand, thirteen".