21774147 has 4 divisors (see below), whose sum is σ = 29032200. Its totient is φ = 14516096.

The previous prime is 21774143. The next prime is 21774163. The reversal of 21774147 is 74147712.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21774147 - 2² = 21774143 is a prime.

It is a super-2 number, since 2×21774147² = 948226955155218, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21774143) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3629022 + ... + 3629027.

It is an arithmetic number, because the mean of its divisors is an integer number (7258050).

Almost surely, 2^21774147 is an apocalyptic number.

21774147 is a deficient number, since it is larger than the sum of its proper divisors (7258053).

21774147 is an equidigital number, since it uses as much as digits as its factorization.

21774147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7258052.

The product of its digits is 10976, while the sum is 33.

The square root of 21774147 is about 4666.2776385466. The cubic root of 21774147 is about 279.2417708773.

The spelling of 21774147 in words is "twenty-one million, seven hundred seventy-four thousand, one hundred forty-seven".