18773155137781 has 6 divisors (see below), whose sum is σ = 20634955647446. Its totient is φ = 17066504670600.

The previous prime is 18773155137761. The next prime is 18773155137833.

18773155137781 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 14001591096900 + 4771564040881 = 3741870^2 + 2184391^2 .

It is not a de Polignac number, because 18773155137781 - 2⁴¹ = 16574131882229 is a prime.

It is a super-2 number, since 2×18773155137781² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18773155137761) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 77575021110 + ... + 77575021351.

Almost surely, 2^{18773155137781} is an apocalyptic number.

18773155137781 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18773155137781 is a deficient number, since it is larger than the sum of its proper divisors (1861800509665).

18773155137781 is a wasteful number, since it uses less digits than its factorization.

18773155137781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155150042483 (or 155150042472 counting only the distinct ones).

The product of its digits is 34574400, while the sum is 64.

The spelling of 18773155137781 in words is "eighteen trillion, seven hundred seventy-three billion, one hundred fifty-five million, one hundred thirty-seven thousand, seven hundred eighty-one".