21343531 has 8 divisors (see below), whose sum is σ = 24035328. Its totient is φ = 18777000.

The previous prime is 21343519. The next prime is 21343579. The reversal of 21343531 is 13534312.

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

It is not a de Polignac number, because 21343531 - 2⁹ = 21343019 is a prime.

It is a super-2 number, since 2×21343531² = 911092631095922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21343501) 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, 30955 + ... + 31636.

It is an arithmetic number, because the mean of its divisors is an integer number (3004416).

Almost surely, 2^21343531 is an apocalyptic number.

21343531 is a deficient number, since it is larger than the sum of its proper divisors (2691797).

21343531 is a wasteful number, since it uses less digits than its factorization.

21343531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62633.

The product of its digits is 1080, while the sum is 22.

The square root of 21343531 is about 4619.9059514237. The cubic root of 21343531 is about 277.3886943704.

Adding to 21343531 its reverse (13534312), we get a palindrome (34877843).

It can be divided in two parts, 2134 and 3531, that added together give a palindrome (5665).

The spelling of 21343531 in words is "twenty-one million, three hundred forty-three thousand, five hundred thirty-one".