16921385 has 8 divisors (see below), whose sum is σ = 21867720. Its totient is φ = 12495744.

The previous prime is 16921379. The next prime is 16921391. The reversal of 16921385 is 58312961.

It is an interprime number because it is at equal distance from previous prime (16921379) and next prime (16921391).

It can be written as a sum of positive squares in 4 ways, for example, as 502681 + 16418704 = 709^2 + 4052^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 16921385 - 2⁴ = 16921369 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 130100 + ... + 130229.

It is an arithmetic number, because the mean of its divisors is an integer number (2733465).

Almost surely, 2^16921385 is an apocalyptic number.

It is an amenable number.

16921385 is a deficient number, since it is larger than the sum of its proper divisors (4946335).

16921385 is a wasteful number, since it uses less digits than its factorization.

16921385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260347.

The product of its digits is 12960, while the sum is 35.

The square root of 16921385 is about 4113.5611093066. The cubic root of 16921385 is about 256.7311910264.

The spelling of 16921385 in words is "sixteen million, nine hundred twenty-one thousand, three hundred eighty-five".