21320145433 has 4 divisors (see below), whose sum is σ = 21320727988. Its totient is φ = 21319562880.

The previous prime is 21320145367. The next prime is 21320145463. The reversal of 21320145433 is 33454102312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15581779929 + 5738365504 = 124827^2 + 75752^2 .

It is a cyclic number.

It is not a de Polignac number, because 21320145433 - 2²⁹ = 20783274521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21320145463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 232416 + ... + 310897.

It is an arithmetic number, because the mean of its divisors is an integer number (5330181997).

Almost surely, 2^21320145433 is an apocalyptic number.

It is an amenable number.

21320145433 is a deficient number, since it is larger than the sum of its proper divisors (582555).

21320145433 is an equidigital number, since it uses as much as digits as its factorization.

21320145433 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 582554.

The product of its (nonzero) digits is 8640, while the sum is 28.

Adding to 21320145433 its reverse (33454102312), we get a palindrome (54774247745).

It can be divided in two parts, 21320 and 145433, that added together give a triangular number (166753 = T₅₇₇).

The spelling of 21320145433 in words is "twenty-one billion, three hundred twenty million, one hundred forty-five thousand, four hundred thirty-three".