21136001 has 4 divisors (see below), whose sum is σ = 21147972. Its totient is φ = 21124032.

The previous prime is 21135997. The next prime is 21136007. The reversal of 21136001 is 10063112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 12609601 + 8526400 = 3551^2 + 2920^2 .

It is a cyclic number.

It is not a de Polignac number, because 21136001 - 2² = 21135997 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21136007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2756 + ... + 7061.

It is an arithmetic number, because the mean of its divisors is an integer number (5286993).

Almost surely, 2^21136001 is an apocalyptic number.

It is an amenable number.

21136001 is a deficient number, since it is larger than the sum of its proper divisors (11971).

21136001 is an equidigital number, since it uses as much as digits as its factorization.

21136001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11970.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 21136001 is about 4597.3906729796. The cubic root of 21136001 is about 276.4867181963.

Adding to 21136001 its reverse (10063112), we get a palindrome (31199113).

The spelling of 21136001 in words is "twenty-one million, one hundred thirty-six thousand, one".