21421744059769 has 3 divisors (see below), whose sum is σ = 21421748688133. Its totient is φ = 21421739431406.

The previous prime is 21421744059713. The next prime is 21421744059797. The reversal of 21421744059769 is 96795044712412.

It is a happy number.

The square root of 21421744059769 is 4628363.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 21421744059769 - 2²¹ = 21421741962617 is a prime.

It is a super-2 number, since 2×21421744059769² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21421744009769) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2314182 + ... + 6942544.

Almost surely, 2^{21421744059769} is an apocalyptic number.

21421744059769 is the 4628363-rd square number.

21421744059769 is the 2314182-nd centered octagonal number.

It is an amenable number.

21421744059769 is a deficient number, since it is larger than the sum of its proper divisors (4628364).

21421744059769 is an frugal number, since it uses more digits than its factorization.

21421744059769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9256726 (or 4628363 counting only the distinct ones).

The product of its (nonzero) digits is 30481920, while the sum is 61.

The spelling of 21421744059769 in words is "twenty-one trillion, four hundred twenty-one billion, seven hundred forty-four million, fifty-nine thousand, seven hundred sixty-nine".