21858845 has 8 divisors (see below), whose sum is σ = 26525880. Its totient is φ = 17290240.

The previous prime is 21858803. The next prime is 21858857. The reversal of 21858845 is 54885812.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 273529 + 21585316 = 523^2 + 4646^2 .

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

It is a de Polignac number, because none of the positive numbers 2^k-21858845 is a prime.

It is a super-3 number, since 3×21858845³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24116 + ... + 25005.

It is an arithmetic number, because the mean of its divisors is an integer number (3315735).

Almost surely, 2^21858845 is an apocalyptic number.

It is an amenable number.

21858845 is a deficient number, since it is larger than the sum of its proper divisors (4667035).

21858845 is an equidigital number, since it uses as much as digits as its factorization.

21858845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49215.

The product of its digits is 102400, while the sum is 41.

The square root of 21858845 is about 4675.3443723431. The cubic root of 21858845 is about 279.6033712514.

The spelling of 21858845 in words is "twenty-one million, eight hundred fifty-eight thousand, eight hundred forty-five".