27991517071401 has 81 divisors (see below), whose sum is σ = 44026628344101. Its totient is φ = 17129681464896.

The previous prime is 27991517071369. The next prime is 27991517071499. The reversal of 27991517071401 is 10417071519972.

The square root of 27991517071401 is 5290701.

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

27991517071401 is a `hidden beast` number, since 2 + 7 + 99 + 15 + 1 + 70 + 71 + 401 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 715548501801 + 27275968569600 = 845901^2 + 5222640^2 .

It is not a de Polignac number, because 27991517071401 - 2⁵ = 27991517071369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (27991517021401) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 60456840096 + ... + 60456840558.

Almost surely, 2^{27991517071401} is an apocalyptic number.

27991517071401 is the 5290701-st square number.

27991517071401 is the 2645351-st centered octagonal number.

It is an amenable number.

27991517071401 is a deficient number, since it is larger than the sum of its proper divisors (16035111272700).

27991517071401 is an frugal number, since it uses more digits than its factorization.

27991517071401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1544 (or 772 counting only the distinct ones).

The product of its (nonzero) digits is 1111320, while the sum is 54.

The spelling of 27991517071401 in words is "twenty-seven trillion, nine hundred ninety-one billion, five hundred seventeen million, seventy-one thousand, four hundred one".