63507321781 has 2 divisors, whose sum is σ = 63507321782. Its totient is φ = 63507321780.

The previous prime is 63507321767. The next prime is 63507321827. The reversal of 63507321781 is 18712370536.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47858562756 + 15648759025 = 218766^2 + 125095^2 .

It is a cyclic number.

It is not a de Polignac number, because 63507321781 - 2¹⁷ = 63507190709 is a prime.

It is a super-2 number, since 2×63507321781² (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 (63507321181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31753660890 + 31753660891.

It is an arithmetic number, because the mean of its divisors is an integer number (31753660891).

Almost surely, 2^63507321781 is an apocalyptic number.

It is an amenable number.

63507321781 is a deficient number, since it is larger than the sum of its proper divisors (1).

63507321781 is an equidigital number, since it uses as much as digits as its factorization.

63507321781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 211680, while the sum is 43.

The spelling of 63507321781 in words is "sixty-three billion, five hundred seven million, three hundred twenty-one thousand, seven hundred eighty-one".