1085209920 has 448 divisors, whose sum is σ = 4119920640. Its totient is φ = 268240896.

The previous prime is 1085209891. The next prime is 1085209949. The reversal of 1085209920 is 299025801.

1085209920 is a `hidden beast` number, since 108 + 520 + 9 + 9 + 20 = 666.

It is an interprime number because it is at equal distance from previous prime (1085209891) and next prime (1085209949).

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 63 ways as a sum of consecutive naturals, for example, 8544897 + ... + 8545023.

Almost surely, 2^1085209920 is an apocalyptic number.

1085209920 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 1085209920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2059960320).

1085209920 is an abundant number, since it is smaller than the sum of its proper divisors (3034710720).

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

1085209920 is a wasteful number, since it uses less digits than its factorization.

1085209920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 1085209920 is about 32942.5244934264. The cubic root of 1085209920 is about 1027.6327070323.

The spelling of 1085209920 in words is "one billion, eighty-five million, two hundred nine thousand, nine hundred twenty".