63553981 has 2 divisors, whose sum is σ = 63553982. Its totient is φ = 63553980.

The previous prime is 63553979. The next prime is 63554003. The reversal of 63553981 is 18935536.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62252100 + 1301881 = 7890^2 + 1141^2 .

It is a cyclic number.

It is not a de Polignac number, because 63553981 - 2¹ = 63553979 is a prime.

It is a super-2 number, since 2×63553981² = 8078217001896722, which contains 22 as substring.

Together with 63553979, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (63553961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31776990 + 31776991.

It is an arithmetic number, because the mean of its divisors is an integer number (31776991).

Almost surely, 2^63553981 is an apocalyptic number.

It is an amenable number.

63553981 is a deficient number, since it is larger than the sum of its proper divisors (1).

63553981 is an equidigital number, since it uses as much as digits as its factorization.

63553981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 97200, while the sum is 40.

The square root of 63553981 is about 7972.0750749099. The cubic root of 63553981 is about 399.0686267931.

The spelling of 63553981 in words is "sixty-three million, five hundred fifty-three thousand, nine hundred eighty-one".