21224130640 has 40 divisors (see below), whose sum is σ = 49355591040. Its totient is φ = 8488020096.

The previous prime is 21224130637. The next prime is 21224130727. The reversal of 21224130640 is 4603142212.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 447757 + ... + 492883.

It is an arithmetic number, because the mean of its divisors is an integer number (1233889776).

Almost surely, 2^21224130640 is an apocalyptic number.

21224130640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21224130640 is an abundant number, since it is smaller than the sum of its proper divisors (28131460400).

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

21224130640 is a wasteful number, since it uses less digits than its factorization.

21224130640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51019 (or 51013 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

Adding to 21224130640 its reverse (4603142212), we get a palindrome (25827272852).

The spelling of 21224130640 in words is "twenty-one billion, two hundred twenty-four million, one hundred thirty thousand, six hundred forty".