It is a tau number, because it is divible by the number of its divisors (40).
It is a self number, because there is not a number n which added to its sum of digits gives 1555440.
It is a congruent number.
It is an unprimeable number.
21555440 is an apocalyptic number.
1555440 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 pseudoperfect number, because it is the sum of a subset of its proper divisors.
1555440 is a wasteful number, since it uses less digits than its factorization.
1555440 is an evil number, because the sum of its binary digits is even.
The square root of 1555440 is about 1247.1728027824. The cubic root of 1555440 is about 115.8646856571.
The spelling of 1555440 in words is "one million, five hundred fifty-five thousand, four hundred forty".