1555665120 has 144 divisors (see below), whose sum is σ = 5341321440. Its totient is φ = 412296192.

The previous prime is 1555665107. The next prime is 1555665143. The reversal of 1555665120 is 215665551.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×1555665120² = 4840187931169228800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 237246 + ... + 243714.

It is an arithmetic number, because the mean of its divisors is an integer number (37092510).

Almost surely, 2^1555665120 is an apocalyptic number.

1555665120 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 1555665120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2670660720).

1555665120 is an abundant number, since it is smaller than the sum of its proper divisors (3785656320).

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

1555665120 is a wasteful number, since it uses less digits than its factorization.

1555665120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6657 (or 6646 counting only the distinct ones).

The product of its (nonzero) digits is 45000, while the sum is 36.

The square root of 1555665120 is about 39441.9208457195. The cubic root of 1555665120 is about 1158.7027511517.

The spelling of 1555665120 in words is "one billion, five hundred fifty-five million, six hundred sixty-five thousand, one hundred twenty".