20725249 has 2 divisors, whose sum is σ = 20725250. Its totient is φ = 20725248.

The previous prime is 20725247. The next prime is 20725273. The reversal of 20725249 is 94252702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20430400 + 294849 = 4520^2 + 543^2 .

It is a cyclic number.

It is not a de Polignac number, because 20725249 - 2¹ = 20725247 is a prime.

It is a super-2 number, since 2×20725249² = 859071892224002, which contains 22 as substring.

Together with 20725247, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 20725249.

It is not a weakly prime, because it can be changed into another prime (20725241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10362624 + 10362625.

It is an arithmetic number, because the mean of its divisors is an integer number (10362625).

Almost surely, 2^20725249 is an apocalyptic number.

It is an amenable number.

20725249 is a deficient number, since it is larger than the sum of its proper divisors (1).

20725249 is an equidigital number, since it uses as much as digits as its factorization.

20725249 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 20725249 is about 4552.4992037341. The cubic root of 20725249 is about 274.6839299785.

The spelling of 20725249 in words is "twenty million, seven hundred twenty-five thousand, two hundred forty-nine".