21203031439 has 4 divisors (see below), whose sum is σ = 21264135624. Its totient is φ = 21141927256.

The previous prime is 21203031401. The next prime is 21203031449. The reversal of 21203031439 is 93413030212.

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 21203031439 - 2²³ = 21194642831 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 (21203031449) 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, 30551572 + ... + 30552265.

It is an arithmetic number, because the mean of its divisors is an integer number (5316033906).

Almost surely, 2^21203031439 is an apocalyptic number.

21203031439 is a deficient number, since it is larger than the sum of its proper divisors (61104185).

21203031439 is an equidigital number, since it uses as much as digits as its factorization.

21203031439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61104184.

The product of its (nonzero) digits is 3888, while the sum is 28.

The spelling of 21203031439 in words is "twenty-one billion, two hundred three million, thirty-one thousand, four hundred thirty-nine".