155199900 has 144 divisors (see below), whose sum is σ = 470219904. Its totient is φ = 39486720.

The previous prime is 155199881. The next prime is 155199907. The reversal of 155199900 is 9991551.

155199900 = 381² + 382² + ... + 804².

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155199907) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 683587 + ... + 683813.

It is an arithmetic number, because the mean of its divisors is an integer number (3265416).

Almost surely, 2^155199900 is an apocalyptic number.

155199900 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 155199900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (235109952).

155199900 is an abundant number, since it is smaller than the sum of its proper divisors (315020004).

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

155199900 is a wasteful number, since it uses less digits than its factorization.

155199900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340 (or 333 counting only the distinct ones).

The product of its (nonzero) digits is 18225, while the sum is 39.

The square root of 155199900 is about 12457.9251884092. The cubic root of 155199900 is about 537.3993610030.

It can be divided in two parts, 15 and 5199900, that added together give a palindrome (5199915).

The spelling of 155199900 in words is "one hundred fifty-five million, one hundred ninety-nine thousand, nine hundred".