21725201 has 8 divisors (see below), whose sum is σ = 23232744. Its totient is φ = 20243200.

The previous prime is 21725183. The next prime is 21725213. The reversal of 21725201 is 10252712.

It can be written as a sum of positive squares in 4 ways, for example, as 4494400 + 17230801 = 2120^2 + 4151^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21725201 - 2²² = 17530897 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21725101) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4610 + ... + 8043.

It is an arithmetic number, because the mean of its divisors is an integer number (2904093).

Almost surely, 2^21725201 is an apocalyptic number.

It is an amenable number.

21725201 is a deficient number, since it is larger than the sum of its proper divisors (1507543).

21725201 is a wasteful number, since it uses less digits than its factorization.

21725201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12771.

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 21725201 is about 4661.0300363761. The cubic root of 21725201 is about 279.0323784916.

Subtracting from 21725201 its product of nonzero digits (280), we obtain a square (21724921 = 4661²).

Adding to 21725201 its reverse (10252712), we get a palindrome (31977913).

The spelling of 21725201 in words is "twenty-one million, seven hundred twenty-five thousand, two hundred one".