21530401024 has 36 divisors (see below), whose sum is σ = 46883677680. Its totient is φ = 9786544640.

The previous prime is 21530400989. The next prime is 21530401027. The reversal of 21530401024 is 42010403512.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a junction number, because it is equal to n+sod(n) for n = 21530400986 and 21530401004.

It is not an unprimeable number, because it can be changed into a prime (21530401027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3820054 + ... + 3825685.

It is an arithmetic number, because the mean of its divisors is an integer number (1302324380).

Almost surely, 2^21530401024 is an apocalyptic number.

It is an amenable number.

21530401024 is an abundant number, since it is smaller than the sum of its proper divisors (25353276656).

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

21530401024 is an equidigital number, since it uses as much as digits as its factorization.

21530401024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7645766 (or 7645752 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

Adding to 21530401024 its reverse (42010403512), we get a palindrome (63540804536).

The spelling of 21530401024 in words is "twenty-one billion, five hundred thirty million, four hundred one thousand, twenty-four".