20340421 has 4 divisors (see below), whose sum is σ = 20393100. Its totient is φ = 20287744.

The previous prime is 20340413. The next prime is 20340443. The reversal of 20340421 is 12404302.

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 6687396 + 13653025 = 2586^2 + 3695^2 .

It is a cyclic number.

It is not a de Polignac number, because 20340421 - 2³ = 20340413 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20340395 and 20340404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20340401) 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, 25756 + ... + 26533.

It is an arithmetic number, because the mean of its divisors is an integer number (5098275).

Almost surely, 2^20340421 is an apocalyptic number.

It is an amenable number.

20340421 is a deficient number, since it is larger than the sum of its proper divisors (52679).

20340421 is an equidigital number, since it uses as much as digits as its factorization.

20340421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52678.

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 20340421 is about 4510.0355874427. The cubic root of 20340421 is about 272.9731800637.

Adding to 20340421 its reverse (12404302), we get a palindrome (32744723).

The spelling of 20340421 in words is "twenty million, three hundred forty thousand, four hundred twenty-one".