618855381 has 12 divisors (see below), whose sum is σ = 902754060. Its totient is φ = 408484800.

The previous prime is 618855371. The next prime is 618855409. The reversal of 618855381 is 183558816.

618855381 is a `hidden beast` number, since 6 + 18 + 8 + 553 + 81 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 415792881 + 203062500 = 20391^2 + 14250^2 .

It is not a de Polignac number, because 618855381 - 2⁷ = 618855253 is a prime.

It is a super-2 number, since 2×618855381² = 765963965185310322, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (618855311) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 339496 + ... + 341313.

It is an arithmetic number, because the mean of its divisors is an integer number (75229505).

Almost surely, 2^618855381 is an apocalyptic number.

It is an amenable number.

618855381 is a deficient number, since it is larger than the sum of its proper divisors (283898679).

618855381 is a wasteful number, since it uses less digits than its factorization.

618855381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 680916 (or 680913 counting only the distinct ones).

The product of its digits is 230400, while the sum is 45.

The square root of 618855381 is about 24876.8040752827. The cubic root of 618855381 is about 852.1768337906.

The spelling of 618855381 in words is "six hundred eighteen million, eight hundred fifty-five thousand, three hundred eighty-one".