21997924169 has 16 divisors (see below), whose sum is σ = 24146337600. Its totient is φ = 19914987456.

The previous prime is 21997924147. The next prime is 21997924213. The reversal of 21997924169 is 96142979912.

It is a de Polignac number, because none of the positive numbers 2^k-21997924169 is a prime.

It is a super-3 number, since 3×21997924169³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Smith number, since the sum of its digits (59) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21997974169) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2571902 + ... + 2580440.

It is an arithmetic number, because the mean of its divisors is an integer number (1509146100).

Almost surely, 2^21997924169 is an apocalyptic number.

It is an amenable number.

21997924169 is a deficient number, since it is larger than the sum of its proper divisors (2148413431).

21997924169 is a wasteful number, since it uses less digits than its factorization.

21997924169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12344.

The product of its digits is 4408992, while the sum is 59.

The spelling of 21997924169 in words is "twenty-one billion, nine hundred ninety-seven million, nine hundred twenty-four thousand, one hundred sixty-nine".