20351421 has 6 divisors (see below), whose sum is σ = 29396510. Its totient is φ = 13567608.

The previous prime is 20351381. The next prime is 20351437. The reversal of 20351421 is 12415302.

It can be written as a sum of positive squares in only one way, i.e., 20115225 + 236196 = 4485^2 + 486^2 .

It is not a de Polignac number, because 20351421 - 2¹⁰ = 20350397 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 20351394 and 20351403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20351521) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1130626 + ... + 1130643.

Almost surely, 2^20351421 is an apocalyptic number.

It is an amenable number.

20351421 is a deficient number, since it is larger than the sum of its proper divisors (9045089).

20351421 is a wasteful number, since it uses less digits than its factorization.

20351421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2261275 (or 2261272 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20351421 is about 4511.2549251843. The cubic root of 20351421 is about 273.0223787153.

Adding to 20351421 its reverse (12415302), we get a palindrome (32766723).

The spelling of 20351421 in words is "twenty million, three hundred fifty-one thousand, four hundred twenty-one".