618988639 has 2 divisors, whose sum is σ = 618988640. Its totient is φ = 618988638.

The previous prime is 618988619. The next prime is 618988691. The reversal of 618988639 is 936889816.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 618988639 - 2⁵ = 618988607 is a prime.

It is a super-2 number, since 2×618988639² = 766293870422144642, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (618988619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 309494319 + 309494320.

It is an arithmetic number, because the mean of its divisors is an integer number (309494320).

Almost surely, 2^618988639 is an apocalyptic number.

618988639 is a deficient number, since it is larger than the sum of its proper divisors (1).

618988639 is an equidigital number, since it uses as much as digits as its factorization.

618988639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4478976, while the sum is 58.

The square root of 618988639 is about 24879.4822896297. The cubic root of 618988639 is about 852.2379957541.

The spelling of 618988639 in words is "six hundred eighteen million, nine hundred eighty-eight thousand, six hundred thirty-nine".