21845161 has 8 divisors (see below), whose sum is σ = 24073280. Its totient is φ = 19695312.

The previous prime is 21845113. The next prime is 21845179. The reversal of 21845161 is 16154812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21845161 - 2²¹ = 19748009 is a prime.

It is a super-2 number, since 2×21845161² = 954422118231842, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21845261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18981 + ... + 20098.

It is an arithmetic number, because the mean of its divisors is an integer number (3009160).

Almost surely, 2^21845161 is an apocalyptic number.

It is an amenable number.

21845161 is a deficient number, since it is larger than the sum of its proper divisors (2228119).

21845161 is a wasteful number, since it uses less digits than its factorization.

21845161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39135.

The product of its digits is 1920, while the sum is 28.

The square root of 21845161 is about 4673.8807216274. The cubic root of 21845161 is about 279.5450136207.

Adding to 21845161 its reverse (16154812), we get a palindrome (37999973).

The spelling of 21845161 in words is "twenty-one million, eight hundred forty-five thousand, one hundred sixty-one".