21023255399 has 4 divisors (see below), whose sum is σ = 21701424960. Its totient is φ = 20345085840.

The previous prime is 21023255387. The next prime is 21023255423. The reversal of 21023255399 is 99355232012.

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 21023255399 - 2³² = 16728288103 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 (21023255329) 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, 339084734 + ... + 339084795.

It is an arithmetic number, because the mean of its divisors is an integer number (5425356240).

Almost surely, 2^21023255399 is an apocalyptic number.

21023255399 is a deficient number, since it is larger than the sum of its proper divisors (678169561).

21023255399 is an equidigital number, since it uses as much as digits as its factorization.

21023255399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 678169560.

The product of its (nonzero) digits is 145800, while the sum is 41.

The spelling of 21023255399 in words is "twenty-one billion, twenty-three million, two hundred fifty-five thousand, three hundred ninety-nine".