20578457 has 2 divisors, whose sum is σ = 20578458. Its totient is φ = 20578456.

The previous prime is 20578421. The next prime is 20578477. The reversal of 20578457 is 75487502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15452761 + 5125696 = 3931^2 + 2264^2 .

It is a cyclic number.

It is not a de Polignac number, because 20578457 - 2¹² = 20574361 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20578457.

It is not a weakly prime, because it can be changed into another prime (20578477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10289228 + 10289229.

It is an arithmetic number, because the mean of its divisors is an integer number (10289229).

Almost surely, 2^20578457 is an apocalyptic number.

It is an amenable number.

20578457 is a deficient number, since it is larger than the sum of its proper divisors (1).

20578457 is an equidigital number, since it uses as much as digits as its factorization.

20578457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 78400, while the sum is 38.

The square root of 20578457 is about 4536.3484213627. The cubic root of 20578457 is about 274.0338859116.

The spelling of 20578457 in words is "twenty million, five hundred seventy-eight thousand, four hundred fifty-seven".