21001445420 has 24 divisors (see below), whose sum is σ = 44395114848. Its totient is φ = 8344944000.

The previous prime is 21001445369. The next prime is 21001445461. The reversal of 21001445420 is 2454410012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3474041 + ... + 3480080.

It is an arithmetic number, because the mean of its divisors is an integer number (1849796452).

Almost surely, 2^21001445420 is an apocalyptic number.

21001445420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001445420 is an abundant number, since it is smaller than the sum of its proper divisors (23393669428).

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

21001445420 is a wasteful number, since it uses less digits than its factorization.

21001445420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6954281 (or 6954279 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 23.

Adding to 21001445420 its reverse (2454410012), we get a palindrome (23455855432).

The spelling of 21001445420 in words is "twenty-one billion, one million, four hundred forty-five thousand, four hundred twenty".