1818398640 has 40 divisors (see below), whose sum is σ = 5637036528. Its totient is φ = 484906240.

The previous prime is 1818398609. The next prime is 1818398641. The reversal of 1818398640 is 468938181.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×1818398640² = 6613147227907699200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 1818398640.

It is not an unprimeable number, because it can be changed into a prime (1818398641) 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, 3788091 + ... + 3788570.

Almost surely, 2^1818398640 is an apocalyptic number.

1818398640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1818398640 is an abundant number, since it is smaller than the sum of its proper divisors (3818637888).

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

1818398640 is a wasteful number, since it uses less digits than its factorization.

1818398640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7576677 (or 7576671 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 48.

The square root of 1818398640 is about 42642.6856565109. The cubic root of 1818398640 is about 1220.5709591227.

The spelling of 1818398640 in words is "one billion, eight hundred eighteen million, three hundred ninety-eight thousand, six hundred forty".