20520451 has 4 divisors (see below), whose sum is σ = 23451952. Its totient is φ = 17588952.

The previous prime is 20520433. The next prime is 20520499. The reversal of 20520451 is 15402502.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20520451 - 2¹¹ = 20518403 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20520421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1465740 + ... + 1465753.

It is an arithmetic number, because the mean of its divisors is an integer number (5862988).

Almost surely, 2^20520451 is an apocalyptic number.

20520451 is a deficient number, since it is larger than the sum of its proper divisors (2931501).

20520451 is an equidigital number, since it uses as much as digits as its factorization.

20520451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2931500.

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 20520451 is about 4529.9504412300. The cubic root of 20520451 is about 273.7761638289.

Adding to 20520451 its reverse (15402502), we get a palindrome (35922953).

The spelling of 20520451 in words is "twenty million, five hundred twenty thousand, four hundred fifty-one".