18023981557156 has 27 divisors (see below), whose sum is σ = 31704238749099. Its totient is φ = 8965863790488.

The previous prime is 18023981557051. The next prime is 18023981557171. The reversal of 18023981557156 is 65175518932081.

The square root of 18023981557156 is 4245466.

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

It is a super-2 number, since 2×18023981557156² (a number of 27 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 = 18023981557094 and 18023981557103.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1689690135 + ... + 1689700801.

Almost surely, 2^{18023981557156} is an apocalyptic number.

18023981557156 is the 4245466-th square number.

It is an amenable number.

18023981557156 is a deficient number, since it is larger than the sum of its proper divisors (13680257191943).

18023981557156 is an frugal number, since it uses more digits than its factorization.

18023981557156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21736 (or 10868 counting only the distinct ones).

The product of its (nonzero) digits is 18144000, while the sum is 61.

The spelling of 18023981557156 in words is "eighteen trillion, twenty-three billion, nine hundred eighty-one million, five hundred fifty-seven thousand, one hundred fifty-six".