21270252440 has 64 divisors (see below), whose sum is σ = 50692080960. Its totient is φ = 8004648960.

The previous prime is 21270252439. The next prime is 21270252463. The reversal of 21270252440 is 4425207212.

It is a super-2 number, since 2×21270252440² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 2873384 + ... + 2880776.

It is an arithmetic number, because the mean of its divisors is an integer number (792063765).

Almost surely, 2^21270252440 is an apocalyptic number.

21270252440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21270252440 is an abundant number, since it is smaller than the sum of its proper divisors (29421828520).

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

21270252440 is a wasteful number, since it uses less digits than its factorization.

21270252440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11652 (or 11648 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 29.

Adding to 21270252440 its reverse (4425207212), we get a palindrome (25695459652).

The spelling of 21270252440 in words is "twenty-one billion, two hundred seventy million, two hundred fifty-two thousand, four hundred forty".