21154543 has 8 divisors (see below), whose sum is σ = 23036400. Its totient is φ = 19349568.

The previous prime is 21154519. The next prime is 21154547. The reversal of 21154543 is 34545112.

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 a de Polignac number, because none of the positive numbers 2^k-21154543 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 (21154547) 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, 18646 + ... + 19747.

It is an arithmetic number, because the mean of its divisors is an integer number (2879550).

Almost surely, 2^21154543 is an apocalyptic number.

21154543 is a deficient number, since it is larger than the sum of its proper divisors (1881857).

21154543 is a wasteful number, since it uses less digits than its factorization.

21154543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38441.

The product of its digits is 2400, while the sum is 25.

The square root of 21154543 is about 4599.4068095788. The cubic root of 21154543 is about 276.5675458217.

Adding to 21154543 its reverse (34545112), we get a palindrome (55699655).

The spelling of 21154543 in words is "twenty-one million, one hundred fifty-four thousand, five hundred forty-three".