21852261 has 24 divisors (see below), whose sum is σ = 34463520. Its totient is φ = 13798512.

The previous prime is 21852247. The next prime is 21852287. The reversal of 21852261 is 16225812.

It is a happy number.

It is not a de Polignac number, because 21852261 - 2⁶ = 21852197 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21852661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2251 + ... + 6983.

It is an arithmetic number, because the mean of its divisors is an integer number (1435980).

Almost surely, 2^21852261 is an apocalyptic number.

It is an amenable number.

21852261 is a deficient number, since it is larger than the sum of its proper divisors (12611259).

21852261 is an equidigital number, since it uses as much as digits as its factorization.

21852261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4767 (or 4755 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 21852261 is about 4674.6402000582. The cubic root of 21852261 is about 279.5752957598.

The spelling of 21852261 in words is "twenty-one million, eight hundred fifty-two thousand, two hundred sixty-one".