21538013484 has 48 divisors (see below), whose sum is σ = 55038493440. Its totient is φ = 6514754880.

The previous prime is 21538013479. The next prime is 21538013491. The reversal of 21538013484 is 48431083512.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1160832 + ... + 1179239.

It is an arithmetic number, because the mean of its divisors is an integer number (1146635280).

Almost surely, 2^21538013484 is an apocalyptic number.

It is an amenable number.

21538013484 is an abundant number, since it is smaller than the sum of its proper divisors (33500479956).

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

21538013484 is a wasteful number, since it uses less digits than its factorization.

21538013484 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2340150 (or 2340148 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 39.

Adding to 21538013484 its reverse (48431083512), we get a palindrome (69969096996).

The spelling of 21538013484 in words is "twenty-one billion, five hundred thirty-eight million, thirteen thousand, four hundred eighty-four".