20819197 has 16 divisors (see below), whose sum is σ = 25234432. Its totient is φ = 16796160.

The previous prime is 20819173. The next prime is 20819213. The reversal of 20819197 is 79191802.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20819197 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20819797) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6733 + ... + 9325.

It is an arithmetic number, because the mean of its divisors is an integer number (1577152).

Almost surely, 2^20819197 is an apocalyptic number.

It is an amenable number.

20819197 is a deficient number, since it is larger than the sum of its proper divisors (4415235).

20819197 is a wasteful number, since it uses less digits than its factorization.

20819197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2668.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 20819197 is about 4562.8058253667. The cubic root of 20819197 is about 275.0983538003.

The spelling of 20819197 in words is "twenty million, eight hundred nineteen thousand, one hundred ninety-seven".