63655831621 has 2 divisors, whose sum is σ = 63655831622. Its totient is φ = 63655831620.

The previous prime is 63655831553. The next prime is 63655831693. The reversal of 63655831621 is 12613855636.

63655831621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 43664699521 + 19991132100 = 208961^2 + 141390^2 .

It is a cyclic number.

It is not a de Polignac number, because 63655831621 - 2⁷ = 63655831493 is a prime.

It is a super-2 number, since 2×63655831621² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (63655837621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31827915810 + 31827915811.

It is an arithmetic number, because the mean of its divisors is an integer number (31827915811).

Almost surely, 2^63655831621 is an apocalyptic number.

It is an amenable number.

63655831621 is a deficient number, since it is larger than the sum of its proper divisors (1).

63655831621 is an equidigital number, since it uses as much as digits as its factorization.

63655831621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 777600, while the sum is 46.

The spelling of 63655831621 in words is "sixty-three billion, six hundred fifty-five million, eight hundred thirty-one thousand, six hundred twenty-one".