20505415 has 16 divisors (see below), whose sum is σ = 29030400. Its totient is φ = 13606560.

The previous prime is 20505409. The next prime is 20505431. The reversal of 20505415 is 51450502.

It is not a de Polignac number, because 20505415 - 2⁹ = 20504903 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8365 + ... + 10534.

It is an arithmetic number, because the mean of its divisors is an integer number (1814400).

Almost surely, 2^20505415 is an apocalyptic number.

20505415 is a deficient number, since it is larger than the sum of its proper divisors (8524985).

20505415 is a wasteful number, since it uses less digits than its factorization.

20505415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18942.

The product of its (nonzero) digits is 1000, while the sum is 22.

The square root of 20505415 is about 4528.2905162986. The cubic root of 20505415 is about 273.7092792651.

Adding to 20505415 its reverse (51450502), we get a palindrome (71955917).

The spelling of 20505415 in words is "twenty million, five hundred five thousand, four hundred fifteen".