20291857 has 2 divisors, whose sum is σ = 20291858. Its totient is φ = 20291856.

The previous prime is 20291839. The next prime is 20291879. The reversal of 20291857 is 75819202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20214016 + 77841 = 4496^2 + 279^2 .

It is a cyclic number.

It is not a de Polignac number, because 20291857 - 2¹¹ = 20289809 is a prime.

It is not a weakly prime, because it can be changed into another prime (20291807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10145928 + 10145929.

It is an arithmetic number, because the mean of its divisors is an integer number (10145929).

Almost surely, 2^20291857 is an apocalyptic number.

It is an amenable number.

20291857 is a deficient number, since it is larger than the sum of its proper divisors (1).

20291857 is an equidigital number, since it uses as much as digits as its factorization.

20291857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 20291857 is about 4504.6483769546. The cubic root of 20291857 is about 272.7557602128.

The spelling of 20291857 in words is "twenty million, two hundred ninety-one thousand, eight hundred fifty-seven".