618987906 has 60 divisors (see below), whose sum is σ = 1422271026. Its totient is φ = 201208320.

The previous prime is 618987883. The next prime is 618987931. The reversal of 618987906 is 609789816.

It can be written as a sum of positive squares in 3 ways, for example, as 342065025 + 276922881 = 18495^2 + 16641^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 271186 + ... + 273458.

Almost surely, 2^618987906 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 618987906, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (711135513).

618987906 is an abundant number, since it is smaller than the sum of its proper divisors (803283120).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

618987906 is a wasteful number, since it uses less digits than its factorization.

618987906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2369 (or 2319 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 54.

The square root of 618987906 is about 24879.4675586115. The cubic root of 618987906 is about 852.2376593501.

The spelling of 618987906 in words is "six hundred eighteen million, nine hundred eighty-seven thousand, nine hundred six".