20025409 has 2 divisors, whose sum is σ = 20025410. Its totient is φ = 20025408.

The previous prime is 20025403. The next prime is 20025419. The reversal of 20025409 is 90452002.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16785409 + 3240000 = 4097^2 + 1800^2 .

It is a cyclic number.

It is not a de Polignac number, because 20025409 - 2⁷ = 20025281 is a prime.

It is equal to p_1272118 and since 20025409 and 1272118 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20025409.

It is not a weakly prime, because it can be changed into another prime (20025403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10012704 + 10012705.

It is an arithmetic number, because the mean of its divisors is an integer number (10012705).

Almost surely, 2^20025409 is an apocalyptic number.

It is an amenable number.

20025409 is a deficient number, since it is larger than the sum of its proper divisors (1).

20025409 is an equidigital number, since it uses as much as digits as its factorization.

20025409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 20025409 is about 4474.9758658567. The cubic root of 20025409 is about 271.5566640760.

The spelling of 20025409 in words is "twenty million, twenty-five thousand, four hundred nine".