21170624549 has 2 divisors, whose sum is σ = 21170624550. Its totient is φ = 21170624548.

The previous prime is 21170624539. The next prime is 21170624593. The reversal of 21170624549 is 94542607112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17512552225 + 3658072324 = 132335^2 + 60482^2 .

It is a cyclic number.

It is not a de Polignac number, because 21170624549 - 2¹² = 21170620453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21170624539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10585312274 + 10585312275.

It is an arithmetic number, because the mean of its divisors is an integer number (10585312275).

Almost surely, 2^21170624549 is an apocalyptic number.

It is an amenable number.

21170624549 is a deficient number, since it is larger than the sum of its proper divisors (1).

21170624549 is an equidigital number, since it uses as much as digits as its factorization.

21170624549 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120960, while the sum is 41.

The spelling of 21170624549 in words is "twenty-one billion, one hundred seventy million, six hundred twenty-four thousand, five hundred forty-nine".