20905051 has 2 divisors, whose sum is σ = 20905052. Its totient is φ = 20905050.

The previous prime is 20905033. The next prime is 20905061. The reversal of 20905051 is 15050902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20905051 - 2¹⁷ = 20773979 is a prime.

It is not a weakly prime, because it can be changed into another prime (20905061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10452525 + 10452526.

It is an arithmetic number, because the mean of its divisors is an integer number (10452526).

Almost surely, 2^20905051 is an apocalyptic number.

20905051 is a deficient number, since it is larger than the sum of its proper divisors (1).

20905051 is an equidigital number, since it uses as much as digits as its factorization.

20905051 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 450, while the sum is 22.

The square root of 20905051 is about 4572.2041730439. The cubic root of 20905051 is about 275.4759844811.

Adding to 20905051 its reverse (15050902), we get a palindrome (35955953).

The spelling of 20905051 in words is "twenty million, nine hundred five thousand, fifty-one".