21139001 has 24 divisors (see below), whose sum is σ = 25421760. Its totient is φ = 17392320.

The previous prime is 21138989. The next prime is 21139009. The reversal of 21139001 is 10093112.

It is a happy number.

It is not a de Polignac number, because 21139001 - 2⁶ = 21138937 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21139009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 346511 + ... + 346571.

It is an arithmetic number, because the mean of its divisors is an integer number (1059240).

Almost surely, 2^21139001 is an apocalyptic number.

It is an amenable number.

21139001 is a deficient number, since it is larger than the sum of its proper divisors (4282759).

21139001 is a wasteful number, since it uses less digits than its factorization.

21139001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177 (or 116 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 17.

The square root of 21139001 is about 4597.7169334356. The cubic root of 21139001 is about 276.4997988939.

The spelling of 21139001 in words is "twenty-one million, one hundred thirty-nine thousand, one".