21242547750 has 32 divisors (see below), whose sum is σ = 53021401056. Its totient is φ = 5664679200.

The previous prime is 21242547721. The next prime is 21242547757. The reversal of 21242547750 is 5774524212.

It is a happy number.

It is a super-2 number, since 2×21242547750² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21242547699 and 21242547708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242547757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14160949 + ... + 14162448.

It is an arithmetic number, because the mean of its divisors is an integer number (1656918783).

Almost surely, 2^21242547750 is an apocalyptic number.

21242547750 is an abundant number, since it is smaller than the sum of its proper divisors (31778853306).

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

21242547750 is a wasteful number, since it uses less digits than its factorization.

21242547750 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28323417 (or 28323407 counting only the distinct ones).

The product of its (nonzero) digits is 156800, while the sum is 39.

The spelling of 21242547750 in words is "twenty-one billion, two hundred forty-two million, five hundred forty-seven thousand, seven hundred fifty".