21234293640 has 256 divisors, whose sum is σ = 81116928000. Its totient is φ = 4840093440.

The previous prime is 21234293627. The next prime is 21234293651. The reversal of 21234293640 is 4639243212.

21234293640 is a `hidden beast` number, since 2 + 1 + 2 + 3 + 4 + 2 + 9 + 3 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21234293595 and 21234293604.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2861535 + ... + 2868945.

It is an arithmetic number, because the mean of its divisors is an integer number (316863000).

Almost surely, 2^21234293640 is an apocalyptic number.

21234293640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21234293640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40558464000).

21234293640 is an abundant number, since it is smaller than the sum of its proper divisors (59882634360).

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

21234293640 is a wasteful number, since it uses less digits than its factorization.

21234293640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7817 (or 7807 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 36.

The spelling of 21234293640 in words is "twenty-one billion, two hundred thirty-four million, two hundred ninety-three thousand, six hundred forty".