21827641 has 4 divisors (see below), whose sum is σ = 23811984. Its totient is φ = 19843300.

The previous prime is 21827623. The next prime is 21827647. The reversal of 21827641 is 14672812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21827641 - 2⁷ = 21827513 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21827647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 992155 + ... + 992176.

It is an arithmetic number, because the mean of its divisors is an integer number (5952996).

Almost surely, 2^21827641 is an apocalyptic number.

It is an amenable number.

21827641 is a deficient number, since it is larger than the sum of its proper divisors (1984343).

21827641 is a wasteful number, since it uses less digits than its factorization.

21827641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1984342.

The product of its digits is 5376, while the sum is 31.

The square root of 21827641 is about 4672.0061001673. The cubic root of 21827641 is about 279.4702611613.

The spelling of 21827641 in words is "twenty-one million, eight hundred twenty-seven thousand, six hundred forty-one".