16509901 has 2 divisors, whose sum is σ = 16509902. Its totient is φ = 16509900.

The previous prime is 16509869. The next prime is 16509919. The reversal of 16509901 is 10990561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14822500 + 1687401 = 3850^2 + 1299^2 .

It is an emirp because it is prime and its reverse (10990561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16509901 - 2⁵ = 16509869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16509931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8254950 + 8254951.

It is an arithmetic number, because the mean of its divisors is an integer number (8254951).

Almost surely, 2^16509901 is an apocalyptic number.

It is an amenable number.

16509901 is a deficient number, since it is larger than the sum of its proper divisors (1).

16509901 is an equidigital number, since it uses as much as digits as its factorization.

16509901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2430, while the sum is 31.

The square root of 16509901 is about 4063.2377483972. The cubic root of 16509901 is about 254.6330798778.

The spelling of 16509901 in words is "sixteen million, five hundred nine thousand, nine hundred one".