20106257 has 16 divisors (see below), whose sum is σ = 21908880. Its totient is φ = 18382848.

The previous prime is 20106253. The next prime is 20106283. The reversal of 20106257 is 75260102.

It is a Cunningham number, because it is equal to 4484²+1.

It can be written as a sum of positive squares in 8 ways, for example, as 1 + 20106256 = 1^2 + 4484^2 .

It is not a de Polignac number, because 20106257 - 2² = 20106253 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20106253) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 146693 + ... + 146829.

It is an arithmetic number, because the mean of its divisors is an integer number (1369305).

Almost surely, 2^20106257 is an apocalyptic number.

It is an amenable number.

20106257 is a deficient number, since it is larger than the sum of its proper divisors (1802623).

20106257 is a wasteful number, since it uses less digits than its factorization.

20106257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 20106257 is about 4484.0001115076. Note that the first 3 decimals coincide. The cubic root of 20106257 is about 271.9216226382.

Adding to 20106257 its reverse (75260102), we get a palindrome (95366359).

The spelling of 20106257 in words is "twenty million, one hundred six thousand, two hundred fifty-seven".