21103151 has 4 divisors (see below), whose sum is σ = 21617904. Its totient is φ = 20588400.

The previous prime is 21103139. The next prime is 21103177. The reversal of 21103151 is 15130112.

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 21103151 - 2⁶ = 21103087 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21103051) 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, 257315 + ... + 257396.

It is an arithmetic number, because the mean of its divisors is an integer number (5404476).

Almost surely, 2^21103151 is an apocalyptic number.

21103151 is a deficient number, since it is larger than the sum of its proper divisors (514753).

21103151 is an equidigital number, since it uses as much as digits as its factorization.

21103151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 514752.

The product of its (nonzero) digits is 30, while the sum is 14.

The square root of 21103151 is about 4593.8166049593. The cubic root of 21103151 is about 276.3434035077.

Adding to 21103151 its reverse (15130112), we get a palindrome (36233263).

The spelling of 21103151 in words is "twenty-one million, one hundred three thousand, one hundred fifty-one".