16549047421 has 2 divisors, whose sum is σ = 16549047422. Its totient is φ = 16549047420.

The previous prime is 16549047413. The next prime is 16549047439. The reversal of 16549047421 is 12474094561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12423554521 + 4125492900 = 111461^2 + 64230^2 .

It is a cyclic number.

It is not a de Polignac number, because 16549047421 - 2³ = 16549047413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16549047721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8274523710 + 8274523711.

It is an arithmetic number, because the mean of its divisors is an integer number (8274523711).

Almost surely, 2^16549047421 is an apocalyptic number.

It is an amenable number.

16549047421 is a deficient number, since it is larger than the sum of its proper divisors (1).

16549047421 is an equidigital number, since it uses as much as digits as its factorization.

16549047421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 241920, while the sum is 43.

The spelling of 16549047421 in words is "sixteen billion, five hundred forty-nine million, forty-seven thousand, four hundred twenty-one".