1213553100 has 72 divisors (see below), whose sum is σ = 3522774528. Its totient is φ = 322548800.

The previous prime is 1213553083. The next prime is 1213553101. The reversal of 1213553100 is 13553121.

It is a super-2 number, since 2×1213553100² = 2945422253039220000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1213553101) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 86797 + ... + 99803.

It is an arithmetic number, because the mean of its divisors is an integer number (48927424).

Almost surely, 2^1213553100 is an apocalyptic number.

1213553100 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 1213553100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1761387264).

1213553100 is an abundant number, since it is smaller than the sum of its proper divisors (2309221428).

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

1213553100 is a wasteful number, since it uses less digits than its factorization.

1213553100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13335 (or 13328 counting only the distinct ones).

The product of its (nonzero) digits is 450, while the sum is 21.

The square root of 1213553100 is about 34836.0890457009. The cubic root of 1213553100 is about 1066.6442454054.

Adding to 1213553100 its sum of digits (21), we get a palindrome (1213553121).

The spelling of 1213553100 in words is "one billion, two hundred thirteen million, five hundred fifty-three thousand, one hundred".