21531223043 has 8 divisors (see below), whose sum is σ = 24298559280. Its totient is φ = 18898878880.

The previous prime is 21531223037. The next prime is 21531223057. The reversal of 21531223043 is 34032213512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21531223043 - 2¹⁴ = 21531206659 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21531223943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33747680 + ... + 33748317.

It is an arithmetic number, because the mean of its divisors is an integer number (3037319910).

Almost surely, 2^21531223043 is an apocalyptic number.

21531223043 is a deficient number, since it is larger than the sum of its proper divisors (2767336237).

21531223043 is a wasteful number, since it uses less digits than its factorization.

21531223043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67496037.

The product of its (nonzero) digits is 4320, while the sum is 26.

Adding to 21531223043 its reverse (34032213512), we get a palindrome (55563436555).

The spelling of 21531223043 in words is "twenty-one billion, five hundred thirty-one million, two hundred twenty-three thousand, forty-three".