1820400208 has 40 divisors (see below), whose sum is σ = 3850485696. Its totient is φ = 826848000.

The previous prime is 1820400187. The next prime is 1820400229. The reversal of 1820400208 is 8020040281.

It is an interprime number because it is at equal distance from previous prime (1820400187) and next prime (1820400229).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 310908 + ... + 316708.

Almost surely, 2^1820400208 is an apocalyptic number.

It is an amenable number.

1820400208 is an abundant number, since it is smaller than the sum of its proper divisors (2030085488).

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

1820400208 is a wasteful number, since it uses less digits than its factorization.

1820400208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7603 (or 7597 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 1820400208 is about 42666.1482676841. The cubic root of 1820400208 is about 1221.0186350585.

Adding to 1820400208 its reverse (8020040281), we get a palindrome (9840440489).

The spelling of 1820400208 in words is "one billion, eight hundred twenty million, four hundred thousand, two hundred eight".