21379601 has 4 divisors (see below), whose sum is σ = 21415092. Its totient is φ = 21344112.

The previous prime is 21379571. The next prime is 21379609. The reversal of 21379601 is 10697312.

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 6130576 + 15249025 = 2476^2 + 3905^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21379601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21379609) 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, 16826 + ... + 18051.

It is an arithmetic number, because the mean of its divisors is an integer number (5353773).

Almost surely, 2^21379601 is an apocalyptic number.

It is an amenable number.

21379601 is a deficient number, since it is larger than the sum of its proper divisors (35491).

21379601 is an equidigital number, since it uses as much as digits as its factorization.

21379601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35490.

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 21379601 is about 4623.8080626254. The cubic root of 21379601 is about 277.5448662678.

The spelling of 21379601 in words is "twenty-one million, three hundred seventy-nine thousand, six hundred one".