21343557 has 8 divisors (see below), whose sum is σ = 28734784. Its totient is φ = 14090688.

The previous prime is 21343519. The next prime is 21343579. The reversal of 21343557 is 75534312.

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

It is not a de Polignac number, because 21343557 - 2⁷ = 21343429 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21343457) 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, 34228 + ... + 34845.

It is an arithmetic number, because the mean of its divisors is an integer number (3591848).

Almost surely, 2^21343557 is an apocalyptic number.

It is an amenable number.

21343557 is a deficient number, since it is larger than the sum of its proper divisors (7391227).

21343557 is a wasteful number, since it uses less digits than its factorization.

21343557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69179.

The product of its digits is 12600, while the sum is 30.

The square root of 21343557 is about 4619.9087653329. The cubic root of 21343557 is about 277.3888070057.

Adding to 21343557 its reverse (75534312), we get a palindrome (96877869).

The spelling of 21343557 in words is "twenty-one million, three hundred forty-three thousand, five hundred fifty-seven".