21601147 has 4 divisors (see below), whose sum is σ = 21610936. Its totient is φ = 21591360.

The previous prime is 21601121. The next prime is 21601171. The reversal of 21601147 is 74110612.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21601147 - 2¹¹ = 21599099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21601187) 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, 148 + ... + 6574.

It is an arithmetic number, because the mean of its divisors is an integer number (5402734).

Almost surely, 2^21601147 is an apocalyptic number.

21601147 is a deficient number, since it is larger than the sum of its proper divisors (9789).

21601147 is an equidigital number, since it uses as much as digits as its factorization.

21601147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9788.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 21601147 is about 4647.7034113635. The cubic root of 21601147 is about 278.5002594688.

Adding to 21601147 its reverse (74110612), we get a palindrome (95711759).

The spelling of 21601147 in words is "twenty-one million, six hundred one thousand, one hundred forty-seven".