20993305 has 8 divisors (see below), whose sum is σ = 25321032. Its totient is φ = 16708608.

The previous prime is 20993281. The next prime is 20993339. The reversal of 20993305 is 50339902.

It can be written as a sum of positive squares in 4 ways, for example, as 5184729 + 15808576 = 2277^2 + 3976^2 .

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 20993305 - 2¹³ = 20985113 is a prime.

It is a Duffinian number.

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, 9672 + ... + 11641.

It is an arithmetic number, because the mean of its divisors is an integer number (3165129).

Almost surely, 2^20993305 is an apocalyptic number.

It is an amenable number.

20993305 is a deficient number, since it is larger than the sum of its proper divisors (4327727).

20993305 is a wasteful number, since it uses less digits than its factorization.

20993305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21515.

The product of its (nonzero) digits is 7290, while the sum is 31.

The square root of 20993305 is about 4581.8451523376. The cubic root of 20993305 is about 275.8630954784.

The spelling of 20993305 in words is "twenty million, nine hundred ninety-three thousand, three hundred five".