21142601 has 4 divisors (see below), whose sum is σ = 21541572. Its totient is φ = 20743632.

The previous prime is 21142531. The next prime is 21142613. The reversal of 21142601 is 10624112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11055625 + 10086976 = 3325^2 + 3176^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21142601 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21142601.

It is not an unprimeable number, because it can be changed into a prime (21142201) 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, 199406 + ... + 199511.

It is an arithmetic number, because the mean of its divisors is an integer number (5385393).

Almost surely, 2^21142601 is an apocalyptic number.

It is an amenable number.

21142601 is a deficient number, since it is larger than the sum of its proper divisors (398971).

21142601 is an equidigital number, since it uses as much as digits as its factorization.

21142601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398970.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 21142601 is about 4598.1084154248. The cubic root of 21142601 is about 276.5154940976.

Adding to 21142601 its reverse (10624112), we get a palindrome (31766713).

The spelling of 21142601 in words is "twenty-one million, one hundred forty-two thousand, six hundred one".