21125310450 has 48 divisors (see below), whose sum is σ = 52854447456. Its totient is φ = 5583558400.

The previous prime is 21125310413. The next prime is 21125310509. The reversal of 21125310450 is 5401352112.

It is a happy number.

It is a super-3 number, since 3×21125310450³ (a number of 32 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21125310450.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 606216 + ... + 640115.

It is an arithmetic number, because the mean of its divisors is an integer number (1101134322).

Almost surely, 2^21125310450 is an apocalyptic number.

21125310450 is an abundant number, since it is smaller than the sum of its proper divisors (31729137006).

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

21125310450 is a wasteful number, since it uses less digits than its factorization.

21125310450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1246459 (or 1246454 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

Adding to 21125310450 its reverse (5401352112), we get a palindrome (26526662562).

The spelling of 21125310450 in words is "twenty-one billion, one hundred twenty-five million, three hundred ten thousand, four hundred fifty".