21249306743 has 4 divisors (see below), whose sum is σ = 24284922000. Its totient is φ = 18213691488.

The previous prime is 21249306739. The next prime is 21249306803. The reversal of 21249306743 is 34760394212.

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

It is a cyclic number.

It is not a de Polignac number, because 21249306743 - 2² = 21249306739 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21249306743.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21249306703) 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, 1517807618 + ... + 1517807631.

It is an arithmetic number, because the mean of its divisors is an integer number (6071230500).

Almost surely, 2^21249306743 is an apocalyptic number.

21249306743 is a deficient number, since it is larger than the sum of its proper divisors (3035615257).

21249306743 is an equidigital number, since it uses as much as digits as its factorization.

21249306743 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3035615256.

The product of its (nonzero) digits is 217728, while the sum is 41.

The spelling of 21249306743 in words is "twenty-one billion, two hundred forty-nine million, three hundred six thousand, seven hundred forty-three".