21885001 has 4 divisors (see below), whose sum is σ = 23172372. Its totient is φ = 20597632.

The previous prime is 21884987. The next prime is 21885013. The reversal of 21885001 is 10058812.

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 19811401 + 2073600 = 4451^2 + 1440^2 .

It is a cyclic number.

It is not a de Polignac number, because 21885001 - 2⁷ = 21884873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21885041) 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, 643660 + ... + 643693.

It is an arithmetic number, because the mean of its divisors is an integer number (5793093).

Almost surely, 2^21885001 is an apocalyptic number.

It is an amenable number.

21885001 is a deficient number, since it is larger than the sum of its proper divisors (1287371).

21885001 is a wasteful number, since it uses less digits than its factorization.

21885001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1287370.

The product of its (nonzero) digits is 640, while the sum is 25.

The square root of 21885001 is about 4678.1407631665. The cubic root of 21885001 is about 279.7148500100.

The spelling of 21885001 in words is "twenty-one million, eight hundred eighty-five thousand, one".