21236002440 has 64 divisors (see below), whose sum is σ = 63729288000. Its totient is φ = 5661042432.

The previous prime is 21236002427. The next prime is 21236002451. The reversal of 21236002440 is 4420063212.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21236002440.

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 15 ways as a sum of consecutive naturals, for example, 351586 + ... + 407534.

It is an arithmetic number, because the mean of its divisors is an integer number (995770125).

Almost surely, 2^21236002440 is an apocalyptic number.

21236002440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21236002440 is an abundant number, since it is smaller than the sum of its proper divisors (42493285560).

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

21236002440 is a wasteful number, since it uses less digits than its factorization.

21236002440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59126 (or 59122 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

Adding to 21236002440 its reverse (4420063212), we get a palindrome (25656065652).

The spelling of 21236002440 in words is "twenty-one billion, two hundred thirty-six million, two thousand, four hundred forty".