21441645 has 32 divisors (see below), whose sum is σ = 38672640. Its totient is φ = 11269440.

The previous prime is 21441617. The next prime is 21441661. The reversal of 21441645 is 54614412.

21441645 is a `hidden beast` number, since 2 + 14 + 4 + 1 + 645 = 666.

It is not a de Polignac number, because 21441645 - 2¹³ = 21433453 is a prime.

It is a super-3 number, since 3×21441645³ (a number of 23 digits) contains 333 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8467 + ... + 10703.

It is an arithmetic number, because the mean of its divisors is an integer number (1208520).

Almost surely, 2^21441645 is an apocalyptic number.

It is an amenable number.

21441645 is a deficient number, since it is larger than the sum of its proper divisors (17230995).

21441645 is a wasteful number, since it uses less digits than its factorization.

21441645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2322 (or 2316 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 21441645 is about 4630.5123906540. The cubic root of 21441645 is about 277.8130870967.

The spelling of 21441645 in words is "twenty-one million, four hundred forty-one thousand, six hundred forty-five".