1819201920 has 64 divisors (see below), whose sum is σ = 5798712240. Its totient is φ = 485120000.

The previous prime is 1819201913. The next prime is 1819201921. The reversal of 1819201920 is 291029181.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1819201921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 471831 + ... + 475670.

Almost surely, 2^1819201920 is an apocalyptic number.

1819201920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1819201920 is an abundant number, since it is smaller than the sum of its proper divisors (3979510320).

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

1819201920 is an equidigital number, since it uses as much as digits as its factorization.

1819201920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 947523 (or 947511 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 33.

The square root of 1819201920 is about 42652.1033479007. The cubic root of 1819201920 is about 1220.7506622748.

The spelling of 1819201920 in words is "one billion, eight hundred nineteen million, two hundred one thousand, nine hundred twenty".