261978857722 has 8 divisors (see below), whose sum is σ = 393605190036. Its totient is φ = 130777127712.

The previous prime is 261978857681. The next prime is 261978857741. The reversal of 261978857722 is 227758879162.

It can be written as a sum of positive squares in 2 ways, for example, as 261856334961 + 122522761 = 511719^2 + 11069^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106149033 + ... + 106151500.

Almost surely, 2^261978857722 is an apocalyptic number.

261978857722 is a deficient number, since it is larger than the sum of its proper divisors (131626332314).

261978857722 is a wasteful number, since it uses less digits than its factorization.

261978857722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212301152.

The product of its digits is 47416320, while the sum is 64.

The spelling of 261978857722 in words is "two hundred sixty-one billion, nine hundred seventy-eight million, eight hundred fifty-seven thousand, seven hundred twenty-two".