21909141 has 12 divisors (see below), whose sum is σ = 33508332. Its totient is φ = 13746816.

The previous prime is 21909131. The next prime is 21909161. The reversal of 21909141 is 14190912.

It can be written as a sum of positive squares in 2 ways, for example, as 6275025 + 15634116 = 2505^2 + 3954^2 .

It is not a de Polignac number, because 21909141 - 2⁶ = 21909077 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21909101) 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 11 ways as a sum of consecutive naturals, for example, 71446 + ... + 71751.

It is an arithmetic number, because the mean of its divisors is an integer number (2792361).

Almost surely, 2^21909141 is an apocalyptic number.

It is an amenable number.

21909141 is a deficient number, since it is larger than the sum of its proper divisors (11599191).

21909141 is a wasteful number, since it uses less digits than its factorization.

21909141 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143220 (or 143217 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 21909141 is about 4680.7201369020. The cubic root of 21909141 is about 279.8176576408.

The spelling of 21909141 in words is "twenty-one million, nine hundred nine thousand, one hundred forty-one".