21335147 has 4 divisors (see below), whose sum is σ = 21491016. Its totient is φ = 21179280.

The previous prime is 21335143. The next prime is 21335173. The reversal of 21335147 is 74153312.

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 21335147 - 2² = 21335143 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21335141) 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, 77729 + ... + 78002.

It is an arithmetic number, because the mean of its divisors is an integer number (5372754).

Almost surely, 2^21335147 is an apocalyptic number.

21335147 is a deficient number, since it is larger than the sum of its proper divisors (155869).

21335147 is a wasteful number, since it uses less digits than its factorization.

21335147 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155868.

The product of its digits is 2520, while the sum is 26.

The square root of 21335147 is about 4618.9984845202. The cubic root of 21335147 is about 277.3523690565.

Adding to 21335147 its reverse (74153312), we get a palindrome (95488459).

The spelling of 21335147 in words is "twenty-one million, three hundred thirty-five thousand, one hundred forty-seven".