21354169 has 4 divisors (see below), whose sum is σ = 21363940. Its totient is φ = 21344400.

The previous prime is 21354167. The next prime is 21354181. The reversal of 21354169 is 96145312.

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 can be written as a sum of positive squares in 2 ways, for example, as 2518569 + 18835600 = 1587^2 + 4340^2 .

It is a cyclic number.

It is not a de Polignac number, because 21354169 - 2¹ = 21354167 is a prime.

It is a super-2 number, since 2×21354169² = 912001067361122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21354169.

It is not an unprimeable number, because it can be changed into a prime (21354167) 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, 67 + ... + 6535.

It is an arithmetic number, because the mean of its divisors is an integer number (5340985).

Almost surely, 2^21354169 is an apocalyptic number.

It is an amenable number.

21354169 is a deficient number, since it is larger than the sum of its proper divisors (9771).

21354169 is an equidigital number, since it uses as much as digits as its factorization.

21354169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9770.

The product of its digits is 6480, while the sum is 31.

The square root of 21354169 is about 4621.0571301381. The cubic root of 21354169 is about 277.4347718886.

The spelling of 21354169 in words is "twenty-one million, three hundred fifty-four thousand, one hundred sixty-nine".