15555555400 has 384 divisors, whose sum is σ = 46498095360. Its totient is φ = 4700160000.

The previous prime is 15555555397. The next prime is 15555555401. The reversal of 15555555400 is 455555551.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (15555555401) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 113544132 + ... + 113544268.

It is an arithmetic number, because the mean of its divisors is an integer number (121088790).

Almost surely, 2^15555555400 is an apocalyptic number.

15555555400 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 15555555400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23249047680).

15555555400 is an abundant number, since it is smaller than the sum of its proper divisors (30942539960).

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

15555555400 is a wasteful number, since it uses less digits than its factorization.

15555555400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345 (or 336 counting only the distinct ones).

The product of its (nonzero) digits is 312500, while the sum is 40.

It can be divided in two parts, 155 and 55555400, that added together give a palindrome (55555555).

The spelling of 15555555400 in words is "fifteen billion, five hundred fifty-five million, five hundred fifty-five thousand, four hundred".