21128151 has 8 divisors (see below), whose sum is σ = 30731904. Its totient is φ = 12804920.

The previous prime is 21128137. The next prime is 21128167. The reversal of 21128151 is 15182112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21128151 - 2⁵ = 21128119 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21128131) 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 7 ways as a sum of consecutive naturals, for example, 320091 + ... + 320156.

It is an arithmetic number, because the mean of its divisors is an integer number (3841488).

Almost surely, 2^21128151 is an apocalyptic number.

21128151 is a deficient number, since it is larger than the sum of its proper divisors (9603753).

21128151 is a wasteful number, since it uses less digits than its factorization.

21128151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 640261.

The product of its digits is 160, while the sum is 21.

The square root of 21128151 is about 4596.5368485415. The cubic root of 21128151 is about 276.4524845130.

The spelling of 21128151 in words is "twenty-one million, one hundred twenty-eight thousand, one hundred fifty-one".