18315481156281 has 9 divisors (see below), whose sum is σ = 26455713548719. Its totient is φ = 12210312211536.

The previous prime is 18315481156253. The next prime is 18315481156327. The reversal of 18315481156281 is 18265118451381.

The square root of 18315481156281 is 4279659.

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

18315481156281 is a `hidden beast` number, since 1 + 8 + 3 + 1 + 5 + 4 + 8 + 1 + 1 + 5 + 628 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14713016420025 + 3602464736256 = 3835755^2 + 1898016^2 .

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

It is not a de Polignac number, because 18315481156281 - 2³¹ = 18313333672633 is a prime.

It is a super-2 number, since 2×18315481156281² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18315481156241) 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, 12125701 + ... + 13552253.

Almost surely, 2^{18315481156281} is an apocalyptic number.

18315481156281 is the 4279659-th square number.

18315481156281 is the 2139830-th centered octagonal number.

It is an amenable number.

18315481156281 is a deficient number, since it is larger than the sum of its proper divisors (8140232392438).

18315481156281 is an frugal number, since it uses more digits than its factorization.

18315481156281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2853112 (or 1426556 counting only the distinct ones).

The product of its digits is 1843200, while the sum is 54.

The spelling of 18315481156281 in words is "eighteen trillion, three hundred fifteen billion, four hundred eighty-one million, one hundred fifty-six thousand, two hundred eighty-one".