155555920 has 80 divisors (see below), whose sum is σ = 391506192. Its totient is φ = 57139200.

The previous prime is 155555909. The next prime is 155555921. The reversal of 155555920 is 29555551.

It can be written as a sum of positive squares in 8 ways, for example, as 1498176 + 154057744 = 1224^2 + 12412^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 155555920.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155555921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 387720 + ... + 388120.

Almost surely, 2^155555920 is an apocalyptic number.

155555920 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 155555920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (195753096).

155555920 is an abundant number, since it is smaller than the sum of its proper divisors (235950272).

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

155555920 is a wasteful number, since it uses less digits than its factorization.

155555920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 800 (or 794 counting only the distinct ones).

The product of its (nonzero) digits is 56250, while the sum is 37.

The square root of 155555920 is about 12472.2058995191. The cubic root of 155555920 is about 537.8099686782.

It can be divided in two parts, 1555 and 55920, that added together give a palindrome (57475).

The spelling of 155555920 in words is "one hundred fifty-five million, five hundred fifty-five thousand, nine hundred twenty".