20420975 has 6 divisors (see below), whose sum is σ = 25322040. Its totient is φ = 16336760.

The previous prime is 20420957. The next prime is 20420977. The reversal of 20420975 is 57902402.

It is not a de Polignac number, because 20420975 - 2¹⁴ = 20404591 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20420977) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 408395 + ... + 408444.

It is an arithmetic number, because the mean of its divisors is an integer number (4220340).

Almost surely, 2^20420975 is an apocalyptic number.

20420975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20420975 is a deficient number, since it is larger than the sum of its proper divisors (4901065).

20420975 is an equidigital number, since it uses as much as digits as its factorization.

20420975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816849 (or 816844 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 20420975 is about 4518.9572912343. The cubic root of 20420975 is about 273.3330565467. Note that the first 3 decimals are identical.

The spelling of 20420975 in words is "twenty million, four hundred twenty thousand, nine hundred seventy-five".