20897805 has 8 divisors (see below), whose sum is σ = 33436512. Its totient is φ = 11145488.

The previous prime is 20897801. The next prime is 20897819. The reversal of 20897805 is 50879802.

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 20897805 - 2² = 20897801 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20897801) 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, 696579 + ... + 696608.

It is an arithmetic number, because the mean of its divisors is an integer number (4179564).

Almost surely, 2^20897805 is an apocalyptic number.

It is an amenable number.

20897805 is a deficient number, since it is larger than the sum of its proper divisors (12538707).

20897805 is a wasteful number, since it uses less digits than its factorization.

20897805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1393195.

The product of its (nonzero) digits is 40320, while the sum is 39.

The square root of 20897805 is about 4571.4117075582. The cubic root of 20897805 is about 275.4441527856. Note that the first 3 decimals are identical.

The spelling of 20897805 in words is "twenty million, eight hundred ninety-seven thousand, eight hundred five".