16915621 has 2 divisors, whose sum is σ = 16915622. Its totient is φ = 16915620.

The previous prime is 16915609. The next prime is 16915627. The reversal of 16915621 is 12651961.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11902500 + 5013121 = 3450^2 + 2239^2 .

It is a cyclic number.

It is not a de Polignac number, because 16915621 - 2⁵ = 16915589 is a prime.

It is a super-2 number, since 2×16915621² = 572276467631282, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16915627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8457810 + 8457811.

It is an arithmetic number, because the mean of its divisors is an integer number (8457811).

Almost surely, 2^16915621 is an apocalyptic number.

It is an amenable number.

16915621 is a deficient number, since it is larger than the sum of its proper divisors (1).

16915621 is an equidigital number, since it uses as much as digits as its factorization.

16915621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 31.

The square root of 16915621 is about 4112.8604401317. The cubic root of 16915621 is about 256.7020372536.

The spelling of 16915621 in words is "sixteen million, nine hundred fifteen thousand, six hundred twenty-one".