21247125400 has 48 divisors (see below), whose sum is σ = 49788599040. Its totient is φ = 8431920000.

The previous prime is 21247125397. The next prime is 21247125409. The reversal of 21247125400 is 452174212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21247125409) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 392851 + ... + 443650.

It is an arithmetic number, because the mean of its divisors is an integer number (1037262480).

Almost surely, 2^21247125400 is an apocalyptic number.

21247125400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21247125400 is an abundant number, since it is smaller than the sum of its proper divisors (28541473640).

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

21247125400 is a wasteful number, since it uses less digits than its factorization.

21247125400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 836644 (or 836635 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 28.

Adding to 21247125400 its reverse (452174212), we get a palindrome (21699299612).

The spelling of 21247125400 in words is "twenty-one billion, two hundred forty-seven million, one hundred twenty-five thousand, four hundred".