21000147 has 16 divisors (see below), whose sum is σ = 33104640. Its totient is φ = 11585952.

The previous prime is 21000143. The next prime is 21000157. The reversal of 21000147 is 74100012.

It is not a de Polignac number, because 21000147 - 2² = 21000143 is a prime.

21000147 is a modest number, since divided by 147 gives 21 as remainder.

It is not an unprimeable number, because it can be changed into a prime (21000143) 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 15 ways as a sum of consecutive naturals, for example, 16633 + ... + 17850.

It is an arithmetic number, because the mean of its divisors is an integer number (2069040).

Almost surely, 2^21000147 is an apocalyptic number.

21000147 is a deficient number, since it is larger than the sum of its proper divisors (12104493).

21000147 is a wasteful number, since it uses less digits than its factorization.

21000147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34522.

The product of its (nonzero) digits is 56, while the sum is 15.

The square root of 21000147 is about 4582.5917339427. The cubic root of 21000147 is about 275.8930613856.

Adding to 21000147 its reverse (74100012), we get a palindrome (95100159).

The spelling of 21000147 in words is "twenty-one million, one hundred forty-seven", and thus it is an aban number.