21154421320 has 16 divisors (see below), whose sum is σ = 47597448060. Its totient is φ = 8461768512.

The previous prime is 21154421311. The next prime is 21154421347. The reversal of 21154421320 is 2312445112.

It can be written as a sum of positive squares in 2 ways, for example, as 17091378756 + 4063042564 = 130734^2 + 63742^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 264430227 + ... + 264430306.

Almost surely, 2^21154421320 is an apocalyptic number.

21154421320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21154421320 is an abundant number, since it is smaller than the sum of its proper divisors (26443026740).

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

21154421320 is a wasteful number, since it uses less digits than its factorization.

21154421320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528860544 (or 528860540 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21154421320 its reverse (2312445112), we get a palindrome (23466866432).

The spelling of 21154421320 in words is "twenty-one billion, one hundred fifty-four million, four hundred twenty-one thousand, three hundred twenty".