21154047643 has 4 divisors (see below), whose sum is σ = 21451992048. Its totient is φ = 20856103240.

The previous prime is 21154047637. The next prime is 21154047647. The reversal of 21154047643 is 34674045112.

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 21154047643 - 2⁵ = 21154047611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21154047647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 148972096 + ... + 148972237.

It is an arithmetic number, because the mean of its divisors is an integer number (5362998012).

Almost surely, 2^21154047643 is an apocalyptic number.

21154047643 is a deficient number, since it is larger than the sum of its proper divisors (297944405).

21154047643 is an equidigital number, since it uses as much as digits as its factorization.

21154047643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297944404.

The product of its (nonzero) digits is 80640, while the sum is 37.

The spelling of 21154047643 in words is "twenty-one billion, one hundred fifty-four million, forty-seven thousand, six hundred forty-three".