6451968451681 has 8 divisors (see below), whose sum is σ = 6473282384744. Its totient is φ = 6430658981760.

The previous prime is 6451968451679. The next prime is 6451968451699. The reversal of 6451968451681 is 1861548691546.

It can be written as a sum of positive squares in 4 ways, for example, as 790114765456 + 5661853686225 = 888884^2 + 2379465^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6451968451681 - 2¹ = 6451968451679 is a prime.

It is a super-2 number, since 2×6451968451681² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6451968451631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1792711 + ... + 4014691.

It is an arithmetic number, because the mean of its divisors is an integer number (809160298093).

Almost surely, 2^{6451968451681} is an apocalyptic number.

It is an amenable number.

6451968451681 is a deficient number, since it is larger than the sum of its proper divisors (21313933063).

6451968451681 is a wasteful number, since it uses less digits than its factorization.

6451968451681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2231571.

The product of its digits is 49766400, while the sum is 64.

The spelling of 6451968451681 in words is "six trillion, four hundred fifty-one billion, nine hundred sixty-eight million, four hundred fifty-one thousand, six hundred eighty-one".