21895645 has 8 divisors (see below), whose sum is σ = 26705880. Its totient is φ = 17229120.

The previous prime is 21895639. The next prime is 21895651. The reversal of 21895645 is 54659812.

It is an interprime number because it is at equal distance from previous prime (21895639) and next prime (21895651).

It can be written as a sum of positive squares in 4 ways, for example, as 21316 + 21874329 = 146^2 + 4677^2 .

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

It is not a de Polignac number, because 21895645 - 2⁵ = 21895613 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21895598 and 21895607.

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, 35590 + ... + 36199.

It is an arithmetic number, because the mean of its divisors is an integer number (3338235).

Almost surely, 2^21895645 is an apocalyptic number.

It is an amenable number.

21895645 is a deficient number, since it is larger than the sum of its proper divisors (4810235).

21895645 is an equidigital number, since it uses as much as digits as its factorization.

21895645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71855.

The product of its digits is 86400, while the sum is 40.

The square root of 21895645 is about 4679.2782563126. The cubic root of 21895645 is about 279.7601900782.

The spelling of 21895645 in words is "twenty-one million, eight hundred ninety-five thousand, six hundred forty-five".