21251223641502 has 48 divisors (see below), whose sum is σ = 46578086646000. Its totient is φ = 7002068032512.

The previous prime is 21251223641471. The next prime is 21251223641507. The reversal of 21251223641502 is 20514632215212.

21251223641502 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 1 + 2 + 2 + 3 + 641 + 5 + 0 + 2 = 666.

It is a super-2 number, since 2×21251223641502² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21251223641507) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17972227 + ... + 19118142.

It is an arithmetic number, because the mean of its divisors is an integer number (970376805125).

Almost surely, 2^{21251223641502} is an apocalyptic number.

21251223641502 is an abundant number, since it is smaller than the sum of its proper divisors (25326863004498).

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

21251223641502 is a wasteful number, since it uses less digits than its factorization.

21251223641502 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37090745 (or 37090742 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

Adding to 21251223641502 its reverse (20514632215212), we get a palindrome (41765855856714).

The spelling of 21251223641502 in words is "twenty-one trillion, two hundred fifty-one billion, two hundred twenty-three million, six hundred forty-one thousand, five hundred two".