21388028023 has 4 divisors (see below), whose sum is σ = 21477517920. Its totient is φ = 21298538128.

The previous prime is 21388027937. The next prime is 21388028029. The reversal of 21388028023 is 32082088312.

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 21388028023 - 2²⁹ = 20851157111 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 (21388028029) 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, 44744590 + ... + 44745067.

It is an arithmetic number, because the mean of its divisors is an integer number (5369379480).

Almost surely, 2^21388028023 is an apocalyptic number.

21388028023 is a deficient number, since it is larger than the sum of its proper divisors (89489897).

21388028023 is an equidigital number, since it uses as much as digits as its factorization.

21388028023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89489896.

The product of its (nonzero) digits is 36864, while the sum is 37.

The spelling of 21388028023 in words is "twenty-one billion, three hundred eighty-eight million, twenty-eight thousand, twenty-three".