20502905 has 4 divisors (see below), whose sum is σ = 24603492. Its totient is φ = 16402320.

The previous prime is 20502887. The next prime is 20502907. The reversal of 20502905 is 50920502.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7333264 + 13169641 = 2708^2 + 3629^2 .

It is a de Polignac number, because none of the positive numbers 2^k-20502905 is a prime.

It is a super-2 number, since 2×20502905² = 840738226878050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20502907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2050286 + ... + 2050295.

It is an arithmetic number, because the mean of its divisors is an integer number (6150873).

Almost surely, 2^20502905 is an apocalyptic number.

It is an amenable number.

20502905 is a deficient number, since it is larger than the sum of its proper divisors (4100587).

20502905 is an equidigital number, since it uses as much as digits as its factorization.

20502905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4100586.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 20502905 is about 4528.0133612877. The cubic root of 20502905 is about 273.6981108604.

The spelling of 20502905 in words is "twenty million, five hundred two thousand, nine hundred five".