21251451312 has 480 divisors, whose sum is σ = 77995008000. Its totient is φ = 5357366784.

The previous prime is 21251451311. The next prime is 21251451323. The reversal of 21251451312 is 21315415212.

It is a happy number.

21251451312 is a `hidden beast` number, since 2 + 12 + 514 + 5 + 131 + 2 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21251451311) 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 95 ways as a sum of consecutive naturals, for example, 14767489 + ... + 14768927.

It is an arithmetic number, because the mean of its divisors is an integer number (162489600).

Almost surely, 2^21251451312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21251451312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38997504000).

21251451312 is an abundant number, since it is smaller than the sum of its proper divisors (56743556688).

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

21251451312 is a wasteful number, since it uses less digits than its factorization.

21251451312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1510 (or 1487 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

Adding to 21251451312 its reverse (21315415212), we get a palindrome (42566866524).

The spelling of 21251451312 in words is "twenty-one billion, two hundred fifty-one million, four hundred fifty-one thousand, three hundred twelve".