21251103213420 has 72 divisors (see below), whose sum is σ = 64857150264816. Its totient is φ = 5632194218112.

The previous prime is 21251103213413. The next prime is 21251103213427. The reversal of 21251103213420 is 2431230115212.

It is a happy number.

21251103213420 is a `hidden beast` number, since 2 + 1 + 25 + 1 + 1 + 0 + 3 + 213 + 420 = 666.

It is an interprime number because it is at equal distance from previous prime (21251103213413) and next prime (21251103213427).

It is not an unprimeable number, because it can be changed into a prime (21251103213427) 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, 362123067 + ... + 362181746.

It is an arithmetic number, because the mean of its divisors is an integer number (900793753678).

Almost surely, 2^{21251103213420} is an apocalyptic number.

21251103213420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21251103213420 is an abundant number, since it is smaller than the sum of its proper divisors (43606047051396).

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

21251103213420 is a wasteful number, since it uses less digits than its factorization.

21251103213420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 724304991 (or 724304986 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

Adding to 21251103213420 its reverse (2431230115212), we get a palindrome (23682333328632).

The spelling of 21251103213420 in words is "twenty-one trillion, two hundred fifty-one billion, one hundred three million, two hundred thirteen thousand, four hundred twenty".