63646421 has 2 divisors, whose sum is σ = 63646422. Its totient is φ = 63646420.

The previous prime is 63646403. The next prime is 63646423. The reversal of 63646421 is 12464636.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63600625 + 45796 = 7975^2 + 214^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-63646421 is a prime.

It is a super-2 number, since 2×63646421² = 8101733812218482, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 63646423, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (63646423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31823210 + 31823211.

It is an arithmetic number, because the mean of its divisors is an integer number (31823211).

Almost surely, 2^63646421 is an apocalyptic number.

It is an amenable number.

63646421 is a deficient number, since it is larger than the sum of its proper divisors (1).

63646421 is an equidigital number, since it uses as much as digits as its factorization.

63646421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 32.

The square root of 63646421 is about 7977.8707058964. The cubic root of 63646421 is about 399.2620163711.

The spelling of 63646421 in words is "sixty-three million, six hundred forty-six thousand, four hundred twenty-one".