21121011983 has 4 divisors (see below), whose sum is σ = 21121577088. Its totient is φ = 21120446880.

The previous prime is 21121011959. The next prime is 21121012021. The reversal of 21121011983 is 38911012112.

It is a happy number.

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 21121011983 - 2²⁰ = 21119963407 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 (21121011913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 222191 + ... + 302672.

It is an arithmetic number, because the mean of its divisors is an integer number (5280394272).

Almost surely, 2^21121011983 is an apocalyptic number.

21121011983 is a deficient number, since it is larger than the sum of its proper divisors (565105).

21121011983 is an equidigital number, since it uses as much as digits as its factorization.

21121011983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 565104.

The product of its (nonzero) digits is 864, while the sum is 29.

The spelling of 21121011983 in words is "twenty-one billion, one hundred twenty-one million, eleven thousand, nine hundred eighty-three".