81277202759769 has 9 divisors (see below), whose sum is σ = 117400443053023. Its totient is φ = 54184783809072.

The previous prime is 81277202759743. The next prime is 81277202759773. The reversal of 81277202759769 is 96795720277218.

It is a happy number.

The square root of 81277202759769 is 9015387.

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

81277202759769 is a `hidden beast` number, since 8 + 1 + 2 + 7 + 7 + 2 + 0 + 27 + 597 + 6 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 3810448449369 + 77466754310400 = 1952037^2 + 8801520^2 .

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

It is not a de Polignac number, because 81277202759769 - 2¹⁵ = 81277202727001 is a prime.

It is a super-2 number, since 2×81277202759769² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81277202759697 and 81277202759706.

It is not an unprimeable number, because it can be changed into a prime (81277202739769) 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, 25543597 + ... + 28548725.

Almost surely, 2^{81277202759769} is an apocalyptic number.

81277202759769 is the 9015387-th square number.

81277202759769 is the 4507694-th centered octagonal number.

It is an amenable number.

81277202759769 is a deficient number, since it is larger than the sum of its proper divisors (36123240293254).

81277202759769 is an frugal number, since it uses more digits than its factorization.

81277202759769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6010264 (or 3005132 counting only the distinct ones).

The product of its (nonzero) digits is 373403520, while the sum is 72.

The spelling of 81277202759769 in words is "eighty-one trillion, two hundred seventy-seven billion, two hundred two million, seven hundred fifty-nine thousand, seven hundred sixty-nine".