21024232440 has 64 divisors (see below), whose sum is σ = 63098624160. Its totient is φ = 5604157440.

The previous prime is 21024232433. The next prime is 21024232441. The reversal of 21024232440 is 4423242012.

It is a super-2 number, since 2×21024232440² (a number of 21 digits) contains 22 as substring.

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 21024232440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21024232441) by changing a digit.

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, 267772 + ... + 337268.

Almost surely, 2^21024232440 is an apocalyptic number.

21024232440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21024232440 is an abundant number, since it is smaller than the sum of its proper divisors (42074391720).

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

21024232440 is a wasteful number, since it uses less digits than its factorization.

21024232440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72032 (or 72028 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 24.

Adding to 21024232440 its reverse (4423242012), we get a palindrome (25447474452).

The spelling of 21024232440 in words is "twenty-one billion, twenty-four million, two hundred thirty-two thousand, four hundred forty".