21421424040 has 64 divisors (see below), whose sum is σ = 64623355200. Its totient is φ = 5680461312.

The previous prime is 21421424033. The next prime is 21421424071. The reversal of 21421424040 is 4042412412.

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 21421424040.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 477157 + ... + 520116.

It is an arithmetic number, because the mean of its divisors is an integer number (1009739925).

Almost surely, 2^21421424040 is an apocalyptic number.

21421424040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21421424040 is an abundant number, since it is smaller than the sum of its proper divisors (43201931160).

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

21421424040 is a wasteful number, since it uses less digits than its factorization.

21421424040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 997466 (or 997462 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 24.

Adding to 21421424040 its reverse (4042412412), we get a palindrome (25463836452).

The spelling of 21421424040 in words is "twenty-one billion, four hundred twenty-one million, four hundred twenty-four thousand, forty".