21021014251243 has 2 divisors, whose sum is σ = 21021014251244. Its totient is φ = 21021014251242.

The previous prime is 21021014251217. The next prime is 21021014251271. The reversal of 21021014251243 is 34215241012012.

It is a happy number.

It is an a-pointer prime, because the next prime (21021014251271) can be obtained adding 21021014251243 to its sum of digits (28).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21021014251243 - 2¹³ = 21021014243051 is a prime.

It is a super-2 number, since 2×21021014251243² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21021014251543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510507125621 + 10510507125622.

It is an arithmetic number, because the mean of its divisors is an integer number (10510507125622).

Almost surely, 2^{21021014251243} is an apocalyptic number.

21021014251243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021014251243 is an equidigital number, since it uses as much as digits as its factorization.

21021014251243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3840, while the sum is 28.

Adding to 21021014251243 its reverse (34215241012012), we get a palindrome (55236255263255).

The spelling of 21021014251243 in words is "twenty-one trillion, twenty-one billion, fourteen million, two hundred fifty-one thousand, two hundred forty-three".