21101021983 has 4 divisors (see below), whose sum is σ = 21129119968. Its totient is φ = 21072924000.

The previous prime is 21101021971. The next prime is 21101021987. The reversal of 21101021983 is 38912010112.

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 21101021983 - 2¹⁷ = 21100890911 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 (21101021987) 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, 14047866 + ... + 14049367.

It is an arithmetic number, because the mean of its divisors is an integer number (5282279992).

Almost surely, 2^21101021983 is an apocalyptic number.

21101021983 is a deficient number, since it is larger than the sum of its proper divisors (28097985).

21101021983 is an equidigital number, since it uses as much as digits as its factorization.

21101021983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28097984.

The product of its (nonzero) digits is 864, while the sum is 28.

The spelling of 21101021983 in words is "twenty-one billion, one hundred one million, twenty-one thousand, nine hundred eighty-three".