20993285 has 8 divisors (see below), whose sum is σ = 25332216. Its totient is φ = 16701120.

The previous prime is 20993281. The next prime is 20993339. The reversal of 20993285 is 58239902.

It can be written as a sum of positive squares in 4 ways, for example, as 2477476 + 18515809 = 1574^2 + 4303^2 .

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

It is not a de Polignac number, because 20993285 - 2² = 20993281 is a prime.

It is a super-3 number, since 3×20993285³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20993281) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10694 + ... + 12503.

It is an arithmetic number, because the mean of its divisors is an integer number (3166527).

Almost surely, 2^20993285 is an apocalyptic number.

It is an amenable number.

20993285 is a deficient number, since it is larger than the sum of its proper divisors (4338931).

20993285 is a wasteful number, since it uses less digits than its factorization.

20993285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23383.

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 20993285 is about 4581.8429698103. The cubic root of 20993285 is about 275.8630078749.

The spelling of 20993285 in words is "twenty million, nine hundred ninety-three thousand, two hundred eighty-five".