21859345 has 4 divisors (see below), whose sum is σ = 26231220. Its totient is φ = 17487472.

The previous prime is 21859337. The next prime is 21859349. The reversal of 21859345 is 54395812.

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 4545424 + 17313921 = 2132^2 + 4161^2 .

It is a cyclic number.

It is not a de Polignac number, because 21859345 - 2³ = 21859337 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21859349) 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, 2185930 + ... + 2185939.

It is an arithmetic number, because the mean of its divisors is an integer number (6557805).

Almost surely, 2^21859345 is an apocalyptic number.

It is an amenable number.

21859345 is a deficient number, since it is larger than the sum of its proper divisors (4371875).

21859345 is an equidigital number, since it uses as much as digits as its factorization.

21859345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4371874.

The product of its digits is 43200, while the sum is 37.

The square root of 21859345 is about 4675.3978440342. The cubic root of 21859345 is about 279.6055031210.

The spelling of 21859345 in words is "twenty-one million, eight hundred fifty-nine thousand, three hundred forty-five".