20634421 has 2 divisors, whose sum is σ = 20634422. Its totient is φ = 20634420.

The previous prime is 20634407. The next prime is 20634443. The reversal of 20634421 is 12443602.

It is a happy number.

It is an a-pointer prime, because the next prime (20634443) can be obtained adding 20634421 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10956100 + 9678321 = 3310^2 + 3111^2 .

It is a cyclic number.

It is not a de Polignac number, because 20634421 - 2⁵ = 20634389 is a prime.

It is a Chen prime.

It is equal to p_1308253 and since 20634421 and 1308253 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 20634392 and 20634401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20634451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10317210 + 10317211.

It is an arithmetic number, because the mean of its divisors is an integer number (10317211).

Almost surely, 2^20634421 is an apocalyptic number.

It is an amenable number.

20634421 is a deficient number, since it is larger than the sum of its proper divisors (1).

20634421 is an equidigital number, since it uses as much as digits as its factorization.

20634421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 20634421 is about 4542.5126306924. The cubic root of 20634421 is about 274.2820767101.

The spelling of 20634421 in words is "twenty million, six hundred thirty-four thousand, four hundred twenty-one".