21441620 has 24 divisors (see below), whose sum is σ = 45294984. Its totient is φ = 8525696.

The previous prime is 21441617. The next prime is 21441661. The reversal of 21441620 is 2614412.

It can be written as a sum of positive squares in 4 ways, for example, as 5071504 + 16370116 = 2252^2 + 4046^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21441592 and 21441601.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 362 + ... + 6558.

It is an arithmetic number, because the mean of its divisors is an integer number (1887291).

Almost surely, 2^21441620 is an apocalyptic number.

21441620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21441620 is an abundant number, since it is smaller than the sum of its proper divisors (23853364).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21441620 is a wasteful number, since it uses less digits than its factorization.

21441620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6379 (or 6377 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 21441620 is about 4630.5096911679. The cubic root of 21441620 is about 277.8129791241.

The spelling of 21441620 in words is "twenty-one million, four hundred forty-one thousand, six hundred twenty".