20720117 has 4 divisors (see below), whose sum is σ = 22603776. Its totient is φ = 18836460.

The previous prime is 20720113. The next prime is 20720131. The reversal of 20720117 is 71102702.

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 20720117 - 2² = 20720113 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 (20720113) 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, 941813 + ... + 941834.

It is an arithmetic number, because the mean of its divisors is an integer number (5650944).

Almost surely, 2^20720117 is an apocalyptic number.

It is an amenable number.

20720117 is a deficient number, since it is larger than the sum of its proper divisors (1883659).

20720117 is a wasteful number, since it uses less digits than its factorization.

20720117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1883658.

The product of its (nonzero) digits is 196, while the sum is 20.

The square root of 20720117 is about 4551.9355223904. The cubic root of 20720117 is about 274.6612556341.

Adding to 20720117 its reverse (71102702), we get a palindrome (91822819).

The spelling of 20720117 in words is "twenty million, seven hundred twenty thousand, one hundred seventeen".