20404261 has 2 divisors, whose sum is σ = 20404262. Its totient is φ = 20404260.

The previous prime is 20404249. The next prime is 20404331. The reversal of 20404261 is 16240402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20079361 + 324900 = 4481^2 + 570^2 .

It is a cyclic number.

It is not a de Polignac number, because 20404261 - 2⁷ = 20404133 is a prime.

It is a super-2 number, since 2×20404261² = 832667733912242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20404361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10202130 + 10202131.

It is an arithmetic number, because the mean of its divisors is an integer number (10202131).

Almost surely, 2^20404261 is an apocalyptic number.

It is an amenable number.

20404261 is a deficient number, since it is larger than the sum of its proper divisors (1).

20404261 is an equidigital number, since it uses as much as digits as its factorization.

20404261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 20404261 is about 4517.1075922541. The cubic root of 20404261 is about 273.2584643580.

Adding to 20404261 its reverse (16240402), we get a palindrome (36644663).

The spelling of 20404261 in words is "twenty million, four hundred four thousand, two hundred sixty-one".