1089386820 has 120 divisors (see below), whose sum is σ = 3426142104. Its totient is φ = 289764864.

The previous prime is 1089386807. The next prime is 1089386833. The reversal of 1089386820 is 286839801.

It is an interprime number because it is at equal distance from previous prime (1089386807) and next prime (1089386833).

It can be written as a sum of positive squares in 4 ways, for example, as 25583364 + 1063803456 = 5058^2 + 32616^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 992512 + ... + 993608.

Almost surely, 2^1089386820 is an apocalyptic number.

1089386820 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 1089386820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1713071052).

1089386820 is an abundant number, since it is smaller than the sum of its proper divisors (2336755284).

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

1089386820 is a wasteful number, since it uses less digits than its factorization.

1089386820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1731 (or 1720 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 45.

The square root of 1089386820 is about 33005.8603887249. The cubic root of 1089386820 is about 1028.9494488507.

The spelling of 1089386820 in words is "one billion, eighty-nine million, three hundred eighty-six thousand, eight hundred twenty".