21012213440249 has 2 divisors, whose sum is σ = 21012213440250. Its totient is φ = 21012213440248.

The previous prime is 21012213440173. The next prime is 21012213440261. The reversal of 21012213440249 is 94204431221012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18748596901225 + 2263616539024 = 4329965^2 + 1504532^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012213440249 - 2²⁸ = 21011945004793 is a prime.

It is a super-2 number, since 2×21012213440249² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21012213440749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506106720124 + 10506106720125.

It is an arithmetic number, because the mean of its divisors is an integer number (10506106720125).

Almost surely, 2^{21012213440249} is an apocalyptic number.

It is an amenable number.

21012213440249 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012213440249 is an equidigital number, since it uses as much as digits as its factorization.

21012213440249 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27648, while the sum is 35.

The spelling of 21012213440249 in words is "twenty-one trillion, twelve billion, two hundred thirteen million, four hundred forty thousand, two hundred forty-nine".