21525101 has 8 divisors (see below), whose sum is σ = 23233560. Its totient is φ = 19824192.

The previous prime is 21525089. The next prime is 21525109. The reversal of 21525101 is 10152512.

It can be written as a sum of positive squares in 4 ways, for example, as 9449476 + 12075625 = 3074^2 + 3475^2 .

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 21525101 - 2¹⁴ = 21508717 is a prime.

It is a Duffinian number.

It is a plaindrome in base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 21525101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21525109) 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, 4991 + ... + 8243.

It is an arithmetic number, because the mean of its divisors is an integer number (2904195).

Almost surely, 2^21525101 is an apocalyptic number.

It is an amenable number.

21525101 is a deficient number, since it is larger than the sum of its proper divisors (1708459).

21525101 is a wasteful number, since it uses less digits than its factorization.

21525101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3775.

The product of its (nonzero) digits is 100, while the sum is 17.

The square root of 21525101 is about 4639.5151686356. The cubic root of 21525101 is about 278.1730587490.

Adding to 21525101 its reverse (10152512), we get a palindrome (31677613).

The spelling of 21525101 in words is "twenty-one million, five hundred twenty-five thousand, one hundred one".