21430553 has 8 divisors (see below), whose sum is σ = 21828000. Its totient is φ = 21035520.

The previous prime is 21430531. The next prime is 21430559. The reversal of 21430553 is 35503412.

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 21430553 - 2¹⁶ = 21365017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21430559) 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, 33113 + ... + 33753.

It is an arithmetic number, because the mean of its divisors is an integer number (2728500).

Almost surely, 2^21430553 is an apocalyptic number.

It is an amenable number.

21430553 is a deficient number, since it is larger than the sum of its proper divisors (397447).

21430553 is an equidigital number, since it uses as much as digits as its factorization.

21430553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1207.

The product of its (nonzero) digits is 1800, while the sum is 23.

The square root of 21430553 is about 4629.3145280916. The cubic root of 21430553 is about 277.7651735733.

Adding to 21430553 its reverse (35503412), we get a palindrome (56933965).

The spelling of 21430553 in words is "twenty-one million, four hundred thirty thousand, five hundred fifty-three".