21737405549 has 2 divisors, whose sum is σ = 21737405550. Its totient is φ = 21737405548.

The previous prime is 21737405509. The next prime is 21737405579. The reversal of 21737405549 is 94550473712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20394696100 + 1342709449 = 142810^2 + 36643^2 .

It is a cyclic number.

It is not a de Polignac number, because 21737405549 - 2²⁸ = 21468970093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21737405509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10868702774 + 10868702775.

It is an arithmetic number, because the mean of its divisors is an integer number (10868702775).

Almost surely, 2^21737405549 is an apocalyptic number.

It is an amenable number.

21737405549 is a deficient number, since it is larger than the sum of its proper divisors (1).

21737405549 is an equidigital number, since it uses as much as digits as its factorization.

21737405549 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1058400, while the sum is 47.

The spelling of 21737405549 in words is "twenty-one billion, seven hundred thirty-seven million, four hundred five thousand, five hundred forty-nine".