1555143440 has 80 divisors (see below), whose sum is σ = 3698572800. Its totient is φ = 607965696.

The previous prime is 1555143419. The next prime is 1555143463. The reversal of 1555143440 is 443415551.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×1555143440² = 4836942237950067200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1555143397 and 1555143406.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 649766 + ... + 652154.

It is an arithmetic number, because the mean of its divisors is an integer number (46232160).

Almost surely, 2^1555143440 is an apocalyptic number.

1555143440 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 1555143440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1849286400).

1555143440 is an abundant number, since it is smaller than the sum of its proper divisors (2143429360).

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

1555143440 is a wasteful number, since it uses less digits than its factorization.

1555143440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2584 (or 2578 counting only the distinct ones).

The product of its (nonzero) digits is 24000, while the sum is 32.

The square root of 1555143440 is about 39435.3070230219. The cubic root of 1555143440 is about 1158.5732160685.

Adding to 1555143440 its reverse (443415551), we get a palindrome (1998558991).

The spelling of 1555143440 in words is "one billion, five hundred fifty-five million, one hundred forty-three thousand, four hundred forty".