155800400 has 90 divisors (see below), whose sum is σ = 435477150. Its totient is φ = 53410560.

The previous prime is 155800387. The next prime is 155800417. The reversal of 155800400 is 4008551.

It can be written as a sum of positive squares in 3 ways, for example, as 8809024 + 146991376 = 2968^2 + 12124^2 .

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 17 ways as a sum of consecutive naturals, for example, 15626 + ... + 23574.

It is an arithmetic number, because the mean of its divisors is an integer number (4838635).

Almost surely, 2^155800400 is an apocalyptic number.

155800400 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 155800400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (217738575).

155800400 is an abundant number, since it is smaller than the sum of its proper divisors (279676750).

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

155800400 is a wasteful number, since it uses less digits than its factorization.

155800400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7981 (or 7963 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 155800400 is about 12482.0030443835. The cubic root of 155800400 is about 538.0915715018.

Adding to 155800400 its reverse (4008551), we get a palindrome (159808951).

The spelling of 155800400 in words is "one hundred fifty-five million, eight hundred thousand, four hundred".