1821690000 has 500 divisors, whose sum is σ = 7136337516. Its totient is φ = 445824000.

The previous prime is 1821689911. The next prime is 1821690007. The reversal of 1821690000 is 961281.

It can be written as a sum of positive squares in 10 ways, for example, as 1329915024 + 491774976 = 36468^2 + 22176^2 .

It is a tau number, because it is divible by the number of its divisors (500).

It is a super-2 number, since 2×1821690000² = 6637108912200000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821690007) by changing a digit.

It is a polite number, since it can be written in 99 ways as a sum of consecutive naturals, for example, 10529914 + ... + 10530086.

Almost surely, 2^1821690000 is an apocalyptic number.

1821690000 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 1821690000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3568168758).

1821690000 is an abundant number, since it is smaller than the sum of its proper divisors (5314647516).

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

1821690000 is a wasteful number, since it uses less digits than its factorization.

1821690000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226 (or 196 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 1821690000 is about 42681.2605249658. The cubic root of 1821690000 is about 1221.3069394776.

The spelling of 1821690000 in words is "one billion, eight hundred twenty-one million, six hundred ninety thousand".