7278951681 has 20 divisors (see below), whose sum is σ = 10888418772. Its totient is φ = 4845974688.

The previous prime is 7278951677. The next prime is 7278951707. The reversal of 7278951681 is 1861598727.

It can be written as a sum of positive squares in 2 ways, for example, as 3292923456 + 3986028225 = 57384^2 + 63135^2 .

It is not a de Polignac number, because 7278951681 - 2² = 7278951677 is a prime.

It is a super-2 number, since 2×7278951681² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (7278951601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1926 + ... + 120671.

Almost surely, 2^7278951681 is an apocalyptic number.

It is an amenable number.

7278951681 is a deficient number, since it is larger than the sum of its proper divisors (3609467091).

7278951681 is a wasteful number, since it uses less digits than its factorization.

7278951681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123342 (or 123333 counting only the distinct ones).

The product of its digits is 1693440, while the sum is 54.

The square root of 7278951681 is about 85316.7725655395. The cubic root of 7278951681 is about 1938.0111833073.

The spelling of 7278951681 in words is "seven billion, two hundred seventy-eight million, nine hundred fifty-one thousand, six hundred eighty-one".