13621037667561 has 9 divisors (see below), whose sum is σ = 19674848179389. Its totient is φ = 9080684397036.

The previous prime is 13621037667547. The next prime is 13621037667571. The reversal of 13621037667561 is 16576673012631.

The square root of 13621037667561 is 3690669.

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

13621037667561 is a `hidden beast` number, since 1 + 3 + 6 + 2 + 1 + 0 + 3 + 76 + 6 + 7 + 561 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 13621037667561 - 2⁹ = 13621037667049 is a prime.

It is a super-2 number, since 2×13621037667561² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 13621037667498 and 13621037667507.

It is not an unprimeable number, because it can be changed into a prime (13621037667571) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 10456896 + ... + 11687118.

Almost surely, 2^{13621037667561} is an apocalyptic number.

13621037667561 is the 3690669-th square number.

13621037667561 is the 1845335-th centered octagonal number.

It is an amenable number.

13621037667561 is a deficient number, since it is larger than the sum of its proper divisors (6053810511828).

13621037667561 is an frugal number, since it uses more digits than its factorization.

13621037667561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2460452 (or 1230226 counting only the distinct ones).

The product of its (nonzero) digits is 5715360, while the sum is 54.

The spelling of 13621037667561 in words is "thirteen trillion, six hundred twenty-one billion, thirty-seven million, six hundred sixty-seven thousand, five hundred sixty-one".