21202109983 has 4 divisors (see below), whose sum is σ = 21602149848. Its totient is φ = 20802070120.

The previous prime is 21202109959. The next prime is 21202110019. The reversal of 21202109983 is 38990120212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21202109983 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 (21202109933) 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, 200019853 + ... + 200019958.

It is an arithmetic number, because the mean of its divisors is an integer number (5400537462).

Almost surely, 2^21202109983 is an apocalyptic number.

21202109983 is a deficient number, since it is larger than the sum of its proper divisors (400039865).

21202109983 is an equidigital number, since it uses as much as digits as its factorization.

21202109983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 400039864.

The product of its (nonzero) digits is 15552, while the sum is 37.

The spelling of 21202109983 in words is "twenty-one billion, two hundred two million, one hundred nine thousand, nine hundred eighty-three".