1856381725081 has 27 divisors (see below), whose sum is σ = 2022651041373. Its totient is φ = 1703004750720.

The previous prime is 1856381725063. The next prime is 1856381725103. The reversal of 1856381725081 is 1805271836581.

The square root of 1856381725081 is 1362491.

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

It can be written as a sum of positive squares in 4 ways, for example, as 644312841481 + 1212068883600 = 802691^2 + 1100940^2 .

It is not a de Polignac number, because 1856381725081 - 2⁵ = 1856381725049 is a prime.

It is a super-2 number, since 2×1856381725081² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1856381725031) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 5508550945 + ... + 5508551281.

Almost surely, 2^{1856381725081} is an apocalyptic number.

1856381725081 is the 1362491-st square number.

1856381725081 is the 681246-th centered octagonal number.

It is an amenable number.

1856381725081 is a deficient number, since it is larger than the sum of its proper divisors (166269316292).

1856381725081 is an frugal number, since it uses more digits than its factorization.

1856381725081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1322 (or 661 counting only the distinct ones).

The product of its (nonzero) digits is 3225600, while the sum is 55.

The spelling of 1856381725081 in words is "one trillion, eight hundred fifty-six billion, three hundred eighty-one million, seven hundred twenty-five thousand, eighty-one".