1802121820 has 24 divisors (see below), whose sum is σ = 3819829104. Its totient is φ = 714110976.

The previous prime is 1802121809. The next prime is 1802121917. The reversal of 1802121820 is 281212081.

It is a super-2 number, since 2×1802121820² = 6495286108240224800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 418917 + ... + 423196.

It is an arithmetic number, because the mean of its divisors is an integer number (159159546).

Almost surely, 2^1802121820 is an apocalyptic number.

1802121820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1802121820 is an abundant number, since it is smaller than the sum of its proper divisors (2017707284).

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

1802121820 is a wasteful number, since it uses less digits than its factorization.

1802121820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 842229 (or 842227 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 25.

The square root of 1802121820 is about 42451.4053948747. The cubic root of 1802121820 is about 1216.9181869023.

The spelling of 1802121820 in words is "one billion, eight hundred two million, one hundred twenty-one thousand, eight hundred twenty".