21924121409 has 4 divisors (see below), whose sum is σ = 22141192020. Its totient is φ = 21707050800.

The previous prime is 21924121399. The next prime is 21924121411. The reversal of 21924121409 is 90412142912.

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

It can be written as a sum of positive squares in 2 ways, for example, as 19835905600 + 2088215809 = 140840^2 + 45697^2 .

It is a cyclic number.

It is not a de Polignac number, because 21924121409 - 2⁴ = 21924121393 is a prime.

It is a super-3 number, since 3×21924121409³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21924123409) 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, 108535154 + ... + 108535355.

It is an arithmetic number, because the mean of its divisors is an integer number (5535298005).

Almost surely, 2^21924121409 is an apocalyptic number.

It is an amenable number.

21924121409 is a deficient number, since it is larger than the sum of its proper divisors (217070611).

21924121409 is a wasteful number, since it uses less digits than its factorization.

21924121409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217070610.

The product of its (nonzero) digits is 10368, while the sum is 35.

The spelling of 21924121409 in words is "twenty-one billion, nine hundred twenty-four million, one hundred twenty-one thousand, four hundred nine".