20505331 has 16 divisors (see below), whose sum is σ = 25682688. Its totient is φ = 15904800.

The previous prime is 20505307. The next prime is 20505341. The reversal of 20505331 is 13350502.

It is a cyclic number.

It is not a de Polignac number, because 20505331 - 2⁷ = 20505203 is a prime.

It is a super-2 number, since 2×20505331² = 840937198839122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20505299 and 20505308.

It is not an unprimeable number, because it can be changed into a prime (20505341) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21321 + ... + 22261.

It is an arithmetic number, because the mean of its divisors is an integer number (1605168).

Almost surely, 2^20505331 is an apocalyptic number.

20505331 is a deficient number, since it is larger than the sum of its proper divisors (5177357).

20505331 is a wasteful number, since it uses less digits than its factorization.

20505331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1242.

The product of its (nonzero) digits is 450, while the sum is 19.

The square root of 20505331 is about 4528.2812412658. The cubic root of 20505331 is about 273.7089055165.

Adding to 20505331 its reverse (13350502), we get a palindrome (33855833).

It can be divided in two parts, 2050 and 5331, that added together give a triangular number (7381 = T₁₂₁).

The spelling of 20505331 in words is "twenty million, five hundred five thousand, three hundred thirty-one".