21042123400 has 48 divisors (see below), whose sum is σ = 48932582400. Its totient is φ = 8415190080.

The previous prime is 21042123343. The next prime is 21042123407. The reversal of 21042123400 is 432124012.

It is not an unprimeable number, because it can be changed into a prime (21042123407) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1761849 + ... + 1773751.

It is an arithmetic number, because the mean of its divisors is an integer number (1019428800).

Almost surely, 2^21042123400 is an apocalyptic number.

21042123400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21042123400 is an abundant number, since it is smaller than the sum of its proper divisors (27890459000).

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

21042123400 is a wasteful number, since it uses less digits than its factorization.

21042123400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20758 (or 20749 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21042123400 its reverse (432124012), we get a palindrome (21474247412).

The spelling of 21042123400 in words is "twenty-one billion, forty-two million, one hundred twenty-three thousand, four hundred".