1815612100 has 27 divisors (see below), whose sum is σ = 3940803111. Its totient is φ = 726074400.

The previous prime is 1815612083. The next prime is 1815612107. The reversal of 1815612100 is 12165181.

It is a happy number.

The square root of 1815612100 is 42610.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 356983236 + 1458628864 = 18894^2 + 38192^2 .

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1815612107) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 423970 + ... + 428230.

Almost surely, 2^1815612100 is an apocalyptic number.

1815612100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1815612100 is the 42610-th square number.

It is an amenable number.

1815612100 is an abundant number, since it is smaller than the sum of its proper divisors (2125191011).

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

1815612100 is an frugal number, since it uses more digits than its factorization.

1815612100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8536 (or 4268 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 25.

The cubic root of 1815612100 is about 1219.9471669318.

Multiplying 1815612100 by its sum of digits (25), we get a square (45390302500 = 213050²).

1815612100 divided by its sum of digits (25) gives a square (72624484 = 8522²).

Adding to 1815612100 its reverse (12165181), we get a palindrome (1827777281).

The spelling of 1815612100 in words is "one billion, eight hundred fifteen million, six hundred twelve thousand, one hundred".