20805007 has 4 divisors (see below), whose sum is σ = 20820520. Its totient is φ = 20789496.

The previous prime is 20804983. The next prime is 20805011. The reversal of 20805007 is 70050802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70050802 = 2 ⋅35025401.

It is a cyclic number.

It is not a de Polignac number, because 20805007 - 2¹¹ = 20802959 is a prime.

It is a Duffinian number.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20805017) 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, 5532 + ... + 8497.

It is an arithmetic number, because the mean of its divisors is an integer number (5205130).

Almost surely, 2^20805007 is an apocalyptic number.

20805007 is a deficient number, since it is larger than the sum of its proper divisors (15513).

20805007 is a wasteful number, since it uses less digits than its factorization.

20805007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15512.

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 20805007 is about 4561.2505960537. The cubic root of 20805007 is about 275.0358388553.

Adding to 20805007 its reverse (70050802), we get a palindrome (90855809).

The spelling of 20805007 in words is "twenty million, eight hundred five thousand, seven".