1801639840 has 288 divisors, whose sum is σ = 5820522624. Its totient is φ = 518031360.

The previous prime is 1801639837. The next prime is 1801639883. The reversal of 1801639840 is 489361081.

It is a super-2 number, since 2×1801639840² = 6491812226150451200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 1801639793 and 1801639802.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1120317 + ... + 1121923.

It is an arithmetic number, because the mean of its divisors is an integer number (20210148).

Almost surely, 2^1801639840 is an apocalyptic number.

1801639840 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 1801639840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2910261312).

1801639840 is an abundant number, since it is smaller than the sum of its proper divisors (4018882784).

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

1801639840 is a wasteful number, since it uses less digits than its factorization.

1801639840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1660 (or 1645 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 40.

The square root of 1801639840 is about 42445.7281713955. The cubic root of 1801639840 is about 1216.8096884057.

The spelling of 1801639840 in words is "one billion, eight hundred one million, six hundred thirty-nine thousand, eight hundred forty".