21473240520 has 32 divisors (see below), whose sum is σ = 64419721920. Its totient is φ = 5726197440.

The previous prime is 21473240483. The next prime is 21473240527. The reversal of 21473240520 is 2504237412.

It is a super-2 number, since 2×21473240520² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (21473240527) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 89471716 + ... + 89471955.

It is an arithmetic number, because the mean of its divisors is an integer number (2013116310).

Almost surely, 2^21473240520 is an apocalyptic number.

21473240520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21473240520 is an abundant number, since it is smaller than the sum of its proper divisors (42946481400).

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

21473240520 is a wasteful number, since it uses less digits than its factorization.

21473240520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178943685 (or 178943681 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 30.

Adding to 21473240520 its reverse (2504237412), we get a palindrome (23977477932).

The spelling of 21473240520 in words is "twenty-one billion, four hundred seventy-three million, two hundred forty thousand, five hundred twenty".