1555320400 has 120 divisors (see below), whose sum is σ = 3836004480. Its totient is φ = 605829120.

The previous prime is 1555320367. The next prime is 1555320427. The reversal of 1555320400 is 40235551.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2622504 + ... + 2623096.

It is an arithmetic number, because the mean of its divisors is an integer number (31966704).

Almost surely, 2^1555320400 is an apocalyptic number.

1555320400 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 1555320400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1918002240).

1555320400 is an abundant number, since it is smaller than the sum of its proper divisors (2280684080).

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

1555320400 is a wasteful number, since it uses less digits than its factorization.

1555320400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 773 (or 762 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 25.

The square root of 1555320400 is about 39437.5506338819. The cubic root of 1555320400 is about 1158.6171591405.

Adding to 1555320400 its reverse (40235551), we get a palindrome (1595555951).

It can be divided in two parts, 15553 and 20400, that added together give a palindrome (35953).

The spelling of 1555320400 in words is "one billion, five hundred fifty-five million, three hundred twenty thousand, four hundred".