105666454977561 has 9 divisors (see below), whose sum is σ = 152629368400639. Its totient is φ = 70444282759536.

The previous prime is 105666454977527. The next prime is 105666454977637. The reversal of 105666454977561 is 165779454666501.

The square root of 105666454977561 is 10279419.

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., 87119169075225 + 18547285902336 = 9333765^2 + 4306656^2 .

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

It is not a de Polignac number, because 105666454977561 - 2²¹ = 105666452880409 is a prime.

It is a super-2 number, since 2×105666454977561² (a number of 29 digits) contains 22 as substring.

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 105666454977561.

It is not an unprimeable number, because it can be changed into a prime (105666454977521) 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, 29125021 + ... + 32551493.

Almost surely, 2^{105666454977561} is an apocalyptic number.

105666454977561 is the 10279419-th square number.

105666454977561 is the 5139710-th centered octagonal number.

It is an amenable number.

105666454977561 is a deficient number, since it is larger than the sum of its proper divisors (46962913423078).

105666454977561 is an frugal number, since it uses more digits than its factorization.

105666454977561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6852952 (or 3426476 counting only the distinct ones).

The product of its (nonzero) digits is 1143072000, while the sum is 72.

The spelling of 105666454977561 in words is "one hundred five trillion, six hundred sixty-six billion, four hundred fifty-four million, nine hundred seventy-seven thousand, five hundred sixty-one".