3979661918281 has 27 divisors (see below), whose sum is σ = 4646800340487. Its totient is φ = 3398367379680.

The previous prime is 3979661918273. The next prime is 3979661918291. The reversal of 3979661918281 is 1828191669793.

The square root of 3979661918281 is 1994909.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1141245660681 + 2838416257600 = 1068291^2 + 1684760^2 .

It is not a de Polignac number, because 3979661918281 - 2³ = 3979661918273 is a prime.

It is a super-3 number, since 3×3979661918281³ (a number of 39 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 3979661918281.

It is not an unprimeable number, because it can be changed into a prime (3979661918261) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 7275432850 + ... + 7275433396.

Almost surely, 2^{3979661918281} is an apocalyptic number.

3979661918281 is the 1994909-th square number.

3979661918281 is the 997455-th centered octagonal number.

It is an amenable number.

3979661918281 is a deficient number, since it is larger than the sum of its proper divisors (667138422206).

3979661918281 is an frugal number, since it uses more digits than its factorization.

3979661918281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2150 (or 1075 counting only the distinct ones).

The product of its digits is 70543872, while the sum is 70.

The spelling of 3979661918281 in words is "three trillion, nine hundred seventy-nine billion, six hundred sixty-one million, nine hundred eighteen thousand, two hundred eighty-one".