21125443400 has 24 divisors (see below), whose sum is σ = 49116656370. Its totient is φ = 8450177280.

The previous prime is 21125443399. The next prime is 21125443403. The reversal of 21125443400 is 434452112.

It can be written as a sum of positive squares in 3 ways, for example, as 15273499396 + 5851944004 = 123586^2 + 76498^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21125443400.

It is not an unprimeable number, because it can be changed into a prime (21125443403) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 52813409 + ... + 52813808.

Almost surely, 2^21125443400 is an apocalyptic number.

21125443400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21125443400 is an abundant number, since it is smaller than the sum of its proper divisors (27991212970).

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

21125443400 is a wasteful number, since it uses less digits than its factorization.

21125443400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105627233 (or 105627224 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 26.

Adding to 21125443400 its reverse (434452112), we get a palindrome (21559895512).

The spelling of 21125443400 in words is "twenty-one billion, one hundred twenty-five million, four hundred forty-three thousand, four hundred".