20520455 has 4 divisors (see below), whose sum is σ = 24624552. Its totient is φ = 16416360.

The previous prime is 20520433. The next prime is 20520499. The reversal of 20520455 is 55402502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55402502 = 2 ⋅27701251.

It is not a de Polignac number, because 20520455 - 2²² = 16326151 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20520455.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2052041 + ... + 2052050.

It is an arithmetic number, because the mean of its divisors is an integer number (6156138).

Almost surely, 2^20520455 is an apocalyptic number.

20520455 is a deficient number, since it is larger than the sum of its proper divisors (4104097).

20520455 is an equidigital number, since it uses as much as digits as its factorization.

20520455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4104096.

The product of its (nonzero) digits is 2000, while the sum is 23.

The square root of 20520455 is about 4529.9508827359. The cubic root of 20520455 is about 273.7761816177.

Adding to 20520455 its reverse (55402502), we get a palindrome (75922957).

The spelling of 20520455 in words is "twenty million, five hundred twenty thousand, four hundred fifty-five".