155521400 has 48 divisors (see below), whose sum is σ = 377319600. Its totient is φ = 59502080.

The previous prime is 155521381. The next prime is 155521409. The reversal of 155521400 is 4125551.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155521409) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 12305 + ... + 21504.

It is an arithmetic number, because the mean of its divisors is an integer number (7860825).

Almost surely, 2^155521400 is an apocalyptic number.

155521400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

155521400 is an abundant number, since it is smaller than the sum of its proper divisors (221798200).

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

155521400 is a wasteful number, since it uses less digits than its factorization.

155521400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33848 (or 33839 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 23.

The square root of 155521400 is about 12470.8219456458. The cubic root of 155521400 is about 537.7701832566.

Adding to 155521400 its reverse (4125551), we get a palindrome (159646951).

The spelling of 155521400 in words is "one hundred fifty-five million, five hundred twenty-one thousand, four hundred".