21251210340 has 24 divisors (see below), whose sum is σ = 59503389120. Its totient is φ = 5666989408.

The previous prime is 21251210333. The next prime is 21251210363. The reversal of 21251210340 is 4301215212.

It is a super-2 number, since 2×21251210340² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 177093360 + ... + 177093479.

It is an arithmetic number, because the mean of its divisors is an integer number (2479307880).

Almost surely, 2^21251210340 is an apocalyptic number.

21251210340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21251210340 is an abundant number, since it is smaller than the sum of its proper divisors (38252178780).

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

21251210340 is a wasteful number, since it uses less digits than its factorization.

21251210340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 354186851 (or 354186849 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

Adding to 21251210340 its reverse (4301215212), we get a palindrome (25552425552).

The spelling of 21251210340 in words is "twenty-one billion, two hundred fifty-one million, two hundred ten thousand, three hundred forty".