6501668981 has 2 divisors, whose sum is σ = 6501668982. Its totient is φ = 6501668980.

The previous prime is 6501668969. The next prime is 6501669017. The reversal of 6501668981 is 1898661056.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5949653956 + 552015025 = 77134^2 + 23495^2 .

It is a cyclic number.

It is not a de Polignac number, because 6501668981 - 2¹⁰ = 6501667957 is a prime.

It is a super-2 number, since 2×6501668981² = 84543399076995156722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6501668941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3250834490 + 3250834491.

It is an arithmetic number, because the mean of its divisors is an integer number (3250834491).

Almost surely, 2^6501668981 is an apocalyptic number.

It is an amenable number.

6501668981 is a deficient number, since it is larger than the sum of its proper divisors (1).

6501668981 is an equidigital number, since it uses as much as digits as its factorization.

6501668981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 622080, while the sum is 50.

The square root of 6501668981 is about 80632.9273994192. The cubic root of 6501668981 is about 1866.4152952575.

The spelling of 6501668981 in words is "six billion, five hundred one million, six hundred sixty-eight thousand, nine hundred eighty-one".