21242450549 has 2 divisors, whose sum is σ = 21242450550. Its totient is φ = 21242450548.

The previous prime is 21242450501. The next prime is 21242450609. The reversal of 21242450549 is 94505424212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20618949649 + 623500900 = 143593^2 + 24970^2 .

It is a cyclic number.

It is not a de Polignac number, because 21242450549 - 2⁸ = 21242450293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21242452549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621225274 + 10621225275.

It is an arithmetic number, because the mean of its divisors is an integer number (10621225275).

Almost surely, 2^21242450549 is an apocalyptic number.

It is an amenable number.

21242450549 is a deficient number, since it is larger than the sum of its proper divisors (1).

21242450549 is an equidigital number, since it uses as much as digits as its factorization.

21242450549 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 115200, while the sum is 38.

The spelling of 21242450549 in words is "twenty-one billion, two hundred forty-two million, four hundred fifty thousand, five hundred forty-nine".