1618655220 has 432 divisors, whose sum is σ = 6483335040. Its totient is φ = 323108352.

The previous prime is 1618655219. The next prime is 1618655237. The reversal of 1618655220 is 225568161.

1618655220 is a `hidden beast` number, since 1 + 6 + 1 + 86 + 552 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 2178169 + ... + 2178911.

It is an arithmetic number, because the mean of its divisors is an integer number (15007720).

Almost surely, 2^1618655220 is an apocalyptic number.

1618655220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1618655220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3241667520).

1618655220 is an abundant number, since it is smaller than the sum of its proper divisors (4864679820).

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

1618655220 is a wasteful number, since it uses less digits than its factorization.

1618655220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 804 (or 792 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 1618655220 is about 40232.5144628073. The cubic root of 1618655220 is about 1174.1352248739.

The spelling of 1618655220 in words is "one billion, six hundred eighteen million, six hundred fifty-five thousand, two hundred twenty".