20520407 has 4 divisors (see below), whose sum is σ = 20539896. Its totient is φ = 20500920.

The previous prime is 20520403. The next prime is 20520413. The reversal of 20520407 is 70402502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70402502 = 2 ⋅35201251.

It is a cyclic number.

It is not a de Polignac number, because 20520407 - 2² = 20520403 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 (20520403) 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, 8069 + ... + 10302.

It is an arithmetic number, because the mean of its divisors is an integer number (5134974).

Almost surely, 2^20520407 is an apocalyptic number.

20520407 is a deficient number, since it is larger than the sum of its proper divisors (19489).

20520407 is a wasteful number, since it uses less digits than its factorization.

20520407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19488.

The product of its (nonzero) digits is 560, while the sum is 20.

The square root of 20520407 is about 4529.9455846621. The cubic root of 20520407 is about 273.7759681516.

Adding to 20520407 its reverse (70402502), we get a palindrome (90922909).

The spelling of 20520407 in words is "twenty million, five hundred twenty thousand, four hundred seven".