63890650781 has 16 divisors (see below), whose sum is σ = 67388468400. Its totient is φ = 60480795648.

The previous prime is 63890650777. The next prime is 63890650799. The reversal of 63890650781 is 18705609836.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 4008156100 + 59882494681 = 63310^2 + 244709^2 .

It is a cyclic number.

It is not a de Polignac number, because 63890650781 - 2² = 63890650777 is a prime.

It is a super-2 number, since 2×63890650781² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (53).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63890650771) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2274635 + ... + 2302551.

It is an arithmetic number, because the mean of its divisors is an integer number (4211779275).

Almost surely, 2^63890650781 is an apocalyptic number.

It is an amenable number.

63890650781 is a deficient number, since it is larger than the sum of its proper divisors (3497817619).

63890650781 is a wasteful number, since it uses less digits than its factorization.

63890650781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29488.

The product of its (nonzero) digits is 2177280, while the sum is 53.

The spelling of 63890650781 in words is "sixty-three billion, eight hundred ninety million, six hundred fifty thousand, seven hundred eighty-one".