21069001 has 4 divisors (see below), whose sum is σ = 22308372. Its totient is φ = 19829632.

The previous prime is 21068977. The next prime is 21069007. The reversal of 21069001 is 10096012.

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 19316025 + 1752976 = 4395^2 + 1324^2 .

It is a cyclic number.

It is not a de Polignac number, because 21069001 - 2¹⁵ = 21036233 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 21069001.

It is not an unprimeable number, because it can be changed into a prime (21069007) 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, 619660 + ... + 619693.

It is an arithmetic number, because the mean of its divisors is an integer number (5577093).

Almost surely, 2^21069001 is an apocalyptic number.

It is an amenable number.

21069001 is a deficient number, since it is larger than the sum of its proper divisors (1239371).

21069001 is a wasteful number, since it uses less digits than its factorization.

21069001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1239370.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 21069001 is about 4590.0981470988. The cubic root of 21069001 is about 276.1942595508.

The spelling of 21069001 in words is "twenty-one million, sixty-nine thousand, one".