21552017 has 4 divisors (see below), whose sum is σ = 22295220. Its totient is φ = 20808816.

The previous prime is 21552007. The next prime is 21552031. The reversal of 21552017 is 71025512.

It is a happy number.

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 13845841 + 7706176 = 3721^2 + 2776^2 .

It is a cyclic number.

It is not a de Polignac number, because 21552017 - 2²² = 17357713 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21551983 and 21552001.

It is not an unprimeable number, because it can be changed into a prime (21552007) 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, 371558 + ... + 371615.

It is an arithmetic number, because the mean of its divisors is an integer number (5573805).

Almost surely, 2^21552017 is an apocalyptic number.

It is an amenable number.

21552017 is a deficient number, since it is larger than the sum of its proper divisors (743203).

21552017 is an equidigital number, since it uses as much as digits as its factorization.

21552017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 743202.

The product of its (nonzero) digits is 700, while the sum is 23.

The square root of 21552017 is about 4642.4149965293. The cubic root of 21552017 is about 278.2889573517.

Adding to 21552017 its reverse (71025512), we get a palindrome (92577529).

The spelling of 21552017 in words is "twenty-one million, five hundred fifty-two thousand, seventeen".