16721357 has 2 divisors, whose sum is σ = 16721358. Its totient is φ = 16721356.

The previous prime is 16721347. The next prime is 16721407. The reversal of 16721357 is 75312761.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15007876 + 1713481 = 3874^2 + 1309^2 .

It is a cyclic number.

It is not a de Polignac number, because 16721357 - 2⁶ = 16721293 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16721347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8360678 + 8360679.

It is an arithmetic number, because the mean of its divisors is an integer number (8360679).

Almost surely, 2^16721357 is an apocalyptic number.

It is an amenable number.

16721357 is a deficient number, since it is larger than the sum of its proper divisors (1).

16721357 is an equidigital number, since it uses as much as digits as its factorization.

16721357 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8820, while the sum is 32.

The square root of 16721357 is about 4089.1755892845. The cubic root of 16721357 is about 255.7155705349.

The spelling of 16721357 in words is "sixteen million, seven hundred twenty-one thousand, three hundred fifty-seven".