20709197 has 4 divisors (see below), whose sum is σ = 20846496. Its totient is φ = 20571900.

The previous prime is 20709133. The next prime is 20709203. The reversal of 20709197 is 79190702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20709197 - 2⁶ = 20709133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20709127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68423 + ... + 68724.

It is an arithmetic number, because the mean of its divisors is an integer number (5211624).

Almost surely, 2^20709197 is an apocalyptic number.

It is an amenable number.

20709197 is a deficient number, since it is larger than the sum of its proper divisors (137299).

20709197 is a wasteful number, since it uses less digits than its factorization.

20709197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137298.

The product of its (nonzero) digits is 7938, while the sum is 35.

The square root of 20709197 is about 4550.7358745592. The cubic root of 20709197 is about 274.6129961259.

Adding to 20709197 its reverse (79190702), we get a palindrome (99899899).

The spelling of 20709197 in words is "twenty million, seven hundred nine thousand, one hundred ninety-seven".