1815000121 has 24 divisors (see below), whose sum is σ = 2180570112. Its totient is φ = 1502793600.

The previous prime is 1815000113. The next prime is 1815000151. The reversal of 1815000121 is 1210005181.

It is a happy number.

It is not a de Polignac number, because 1815000121 - 2³ = 1815000113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1815000151) 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, 49536 + ... + 77998.

It is an arithmetic number, because the mean of its divisors is an integer number (90857088).

Almost surely, 2^1815000121 is an apocalyptic number.

1815000121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1815000121 is a deficient number, since it is larger than the sum of its proper divisors (365569991).

1815000121 is a wasteful number, since it uses less digits than its factorization.

1815000121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28533 (or 28522 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 19.

The square root of 1815000121 is about 42602.8182283755. The cubic root of 1815000121 is about 1219.8100844303.

The spelling of 1815000121 in words is "one billion, eight hundred fifteen million, one hundred twenty-one", and thus it is an aban number.