21456423534 has 48 divisors (see below), whose sum is σ = 53106026112. Its totient is φ = 5658835104.

The previous prime is 21456423511. The next prime is 21456423551. The reversal of 21456423534 is 43532465412.

It is a super-2 number, since 2×21456423534² (a number of 21 digits) contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 21456423492 and 21456423501.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1504344 + ... + 1518539.

It is an arithmetic number, because the mean of its divisors is an integer number (1106375544).

Almost surely, 2^21456423534 is an apocalyptic number.

21456423534 is an abundant number, since it is smaller than the sum of its proper divisors (31649602578).

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

21456423534 is a wasteful number, since it uses less digits than its factorization.

21456423534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3022921 (or 3022908 counting only the distinct ones).

The product of its digits is 345600, while the sum is 39.

Adding to 21456423534 its reverse (43532465412), we get a palindrome (64988888946).

The spelling of 21456423534 in words is "twenty-one billion, four hundred fifty-six million, four hundred twenty-three thousand, five hundred thirty-four".