21030061800 has 96 divisors (see below), whose sum is σ = 71119867680. Its totient is φ = 5098195200.

The previous prime is 21030061751. The next prime is 21030061849. The reversal of 21030061800 is 816003012.

It is an interprime number because it is at equal distance from previous prime (21030061751) and next prime (21030061849).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1586587 + ... + 1599786.

It is an arithmetic number, because the mean of its divisors is an integer number (740831955).

Almost surely, 2^21030061800 is an apocalyptic number.

21030061800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21030061800 is an abundant number, since it is smaller than the sum of its proper divisors (50089805880).

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

21030061800 is a wasteful number, since it uses less digits than its factorization.

21030061800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3186403 (or 3186394 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

Adding to 21030061800 its reverse (816003012), we get a palindrome (21846064812).

The spelling of 21030061800 in words is "twenty-one billion, thirty million, sixty-one thousand, eight hundred".