20818461 has 4 divisors (see below), whose sum is σ = 27757952. Its totient is φ = 13878972.

The previous prime is 20818459. The next prime is 20818477. The reversal of 20818461 is 16481802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20818461 - 2¹ = 20818459 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20818481) 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, 3469741 + ... + 3469746.

It is an arithmetic number, because the mean of its divisors is an integer number (6939488).

Almost surely, 2^20818461 is an apocalyptic number.

It is an amenable number.

20818461 is a deficient number, since it is larger than the sum of its proper divisors (6939491).

20818461 is an equidigital number, since it uses as much as digits as its factorization.

20818461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6939490.

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 20818461 is about 4562.7251725257. The cubic root of 20818461 is about 275.0951120042.

The spelling of 20818461 in words is "twenty million, eight hundred eighteen thousand, four hundred sixty-one".