13771231543521 has 21 divisors (see below), whose sum is σ = 20647552252449. Its totient is φ = 9180754231716.

The previous prime is 13771231543519. The next prime is 13771231543523. The reversal of 13771231543521 is 12534513217731.

It is a happy number.

The square root of 13771231543521 is 3710961.

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

13771231543521 is a `hidden beast` number, since 1 + 3 + 7 + 71 + 2 + 3 + 1 + 54 + 3 + 521 = 666.

It is an interprime number because it is at equal distance from previous prime (13771231543519) and next prime (13771231543523).

It is not a de Polignac number, because 13771231543521 - 2¹ = 13771231543519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (13771231543523) by changing a digit.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 100127226 + ... + 100264668.

Almost surely, 2^{13771231543521} is an apocalyptic number.

13771231543521 is the 3710961-st square number.

13771231543521 is the 1855481-st centered octagonal number.

It is an amenable number.

13771231543521 is a deficient number, since it is larger than the sum of its proper divisors (6876320708928).

13771231543521 is an frugal number, since it uses more digits than its factorization.

13771231543521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274904 (or 137446 counting only the distinct ones).

The product of its digits is 529200, while the sum is 45.

The spelling of 13771231543521 in words is "thirteen trillion, seven hundred seventy-one billion, two hundred thirty-one million, five hundred forty-three thousand, five hundred twenty-one".