16521919 has 2 divisors, whose sum is σ = 16521920. Its totient is φ = 16521918.

The previous prime is 16521907. The next prime is 16521937. The reversal of 16521919 is 91912561.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 16521919 - 2¹³ = 16513727 is a prime.

It is a super-2 number, since 2×16521919² = 545947614885122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16521979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8260959 + 8260960.

It is an arithmetic number, because the mean of its divisors is an integer number (8260960).

Almost surely, 2^16521919 is an apocalyptic number.

16521919 is a deficient number, since it is larger than the sum of its proper divisors (1).

16521919 is an equidigital number, since it uses as much as digits as its factorization.

16521919 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4860, while the sum is 34.

The square root of 16521919 is about 4064.7163492672. The cubic root of 16521919 is about 254.6948496430.

The spelling of 16521919 in words is "sixteen million, five hundred twenty-one thousand, nine hundred nineteen".