1638551040 has 320 divisors, whose sum is σ = 6198888960. Its totient is φ = 361267200.

The previous prime is 1638551029. The next prime is 1638551153. The reversal of 1638551040 is 401558361.

It is a tau number, because it is divible by the number of its divisors (320).

It is a junction number, because it is equal to n+sod(n) for n = 1638550992 and 1638551010.

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 31 ways as a sum of consecutive naturals, for example, 1558515 + ... + 1559565.

It is an arithmetic number, because the mean of its divisors is an integer number (19371528).

Almost surely, 2^1638551040 is an apocalyptic number.

1638551040 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 1638551040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3099444480).

1638551040 is an abundant number, since it is smaller than the sum of its proper divisors (4560337920).

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

1638551040 is a wasteful number, since it uses less digits than its factorization.

1638551040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1113 (or 1097 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 33.

The square root of 1638551040 is about 40479.0197509772. The cubic root of 1638551040 is about 1178.9263047615.

The spelling of 1638551040 in words is "one billion, six hundred thirty-eight million, five hundred fifty-one thousand, forty".