618999881 has 2 divisors, whose sum is σ = 618999882. Its totient is φ = 618999880.

The previous prime is 618999863. The next prime is 618999883. The reversal of 618999881 is 188999816.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 618765625 + 234256 = 24875^2 + 484^2 .

It is a cyclic number.

It is not a de Polignac number, because 618999881 - 2⁶ = 618999817 is a prime.

It is a super-2 number, since 2×618999881² = 766321705356028322, which contains 22 as substring.

Together with 618999883, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 618999881.

It is not a weakly prime, because it can be changed into another prime (618999883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 309499940 + 309499941.

It is an arithmetic number, because the mean of its divisors is an integer number (309499941).

Almost surely, 2^618999881 is an apocalyptic number.

It is an amenable number.

618999881 is a deficient number, since it is larger than the sum of its proper divisors (1).

618999881 is an equidigital number, since it uses as much as digits as its factorization.

618999881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2239488, while the sum is 59.

The square root of 618999881 is about 24879.7082177424. The cubic root of 618999881 is about 852.2431551388.

The spelling of 618999881 in words is "six hundred eighteen million, nine hundred ninety-nine thousand, eight hundred eighty-one".