1009121820 has 96 divisors (see below), whose sum is σ = 3254017536. Its totient is φ = 228883200.

The previous prime is 1009121809. The next prime is 1009121821. The reversal of 1009121820 is 281219001.

It is a super-2 number, since 2×1009121820² = 2036653695200224800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1009121821) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 45850 + ... + 64190.

It is an arithmetic number, because the mean of its divisors is an integer number (33896016).

Almost surely, 2^1009121820 is an apocalyptic number.

1009121820 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 1009121820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1627008768).

1009121820 is an abundant number, since it is smaller than the sum of its proper divisors (2244895716).

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

1009121820 is a wasteful number, since it uses less digits than its factorization.

1009121820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18491 (or 18489 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 24.

The square root of 1009121820 is about 31766.6778244122. The cubic root of 1009121820 is about 1003.0314079469.

The spelling of 1009121820 in words is "one billion, nine million, one hundred twenty-one thousand, eight hundred twenty".