21864895 has 16 divisors (see below), whose sum is σ = 28365120. Its totient is φ = 16084224.

The previous prime is 21864893. The next prime is 21864923. The reversal of 21864895 is 59846812.

It is a happy number.

It is not a de Polignac number, because 21864895 - 2¹ = 21864893 is a prime.

It is a super-2 number, since 2×21864895² = 956147266722050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21864893) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22867 + ... + 23803.

It is an arithmetic number, because the mean of its divisors is an integer number (1772820).

Almost surely, 2^21864895 is an apocalyptic number.

21864895 is a deficient number, since it is larger than the sum of its proper divisors (6500225).

21864895 is a wasteful number, since it uses less digits than its factorization.

21864895 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1314.

The product of its digits is 138240, while the sum is 43.

The square root of 21864895 is about 4675.9913387430. The cubic root of 21864895 is about 279.6291646904.

The spelling of 21864895 in words is "twenty-one million, eight hundred sixty-four thousand, eight hundred ninety-five".